document_title: Mahakali– Anth hi Aarambh hai

question_text: who played the role of parvati in mahakali

text: Mahakali– Anth hi Aarambh hai

text: Plot[edit]

text: Parvati is introduced as a sweet, motherly and docile woman who, like every other individual of the time period, is brainwashed into believing men are superior to women. Shiva, her husband doesn't believe that. He along with Lord Vishnu orchestrates Parvati receiving a vision of Mahakali, a terrific warrior goddess, fighting off hordes of demons.

text: Like most stories in Hindu Mythology, this story begins with the war between the gods and the demons. However, this time, the gods defeated and driven out of their homes in heaven. They are forced to seek refuge with Parvati and Shiva, at their home in mount Kailash.

text: The demon king and Primary antagonist, Shumbh sends his messengers to Kailash, declaring war upon Shiva and Parvati for sheltering the gods. But smitten by Parvati's beauty, the demons retreat without saying much and inform Shumbh and his simpleton brother Nishumbh of Parvati's gorgeousness.

text: Meanwhile, Shiva Informs Parvati and the gods that only a woman can kill the demon duo due to a celestial boon. He also taunts Parvati, telling her that it was ineligent of the demons to get such a specific boon, as no woman is tough enough to battle men. Parvati silently nods, and Shiva wows to change her opinion.

text: The demon king's envoy arrives with Shumbh's proposal: if Parvati were to marry Shumbh, he would give up on hunting the gods. The gods violently react to the messenger's words, threatening to kill him. But Parvati stops them and declines Shumbh's proposal, but also warns the demon to use his better judgement and not disrespect a woman. She then shows him out.

text: Parvati complains to Shiva of her mistreatment. He simply replies with "Why do women come to men to solve their problems. Women need to fight their own battles." And then proceeds to speak in metaphoric sentences that become crucial to Parvati only later. He falls into a trance, as he usually does and Parvati is left to ponder on the meaning of his words.

text: Out of reverence to Parvati's gentleness and hospitality, the gods vow to protect her. Undettered, Shumbh sends his trusted, Dhoomralochan to bring Parvati to hell, his capital by force. When he attacks with an army of 60,000 men and insults the intelligence of women, Parvati loses her temper and screams loudly into space. Due to the cosmic vibrations from her shriek, Dhoomralochan and his army are turned to dust.

text: This marks the beginning of Parvati's transition into the warrior Goddess Mahakali. It is at this moment that the other Goddesses like Lakshmi and Saraswathi realize that there is something different about Parvati.

text: Shumbh is infuriated and sends another horde of demons to bring Parvati to him and defeat the gods. In this war, the gods are lead by the Goddess Narasimhi who, due to her horrific appearance is mistaken to be the warrior goddess from Parvati's vision.

text: As the demons slaughtered god after another, the commanders, Chand and Mund make a dash for Goddess Lakshmi, who they decide to kidnap.

text: As she watches in horror, Parvati remembers something Shiva had told her earlier before he went into a trance : "If a woman gives up her 'shanka' (doubt, hesitation, fear) she becomes 'Shankar' (God, supreme force). And this end will mark a greater beginning." Parvati rushes forwards to protect Goddess Lakshmi who is trying to defend herself but in vain.

text: As she runs towards the demons, her anger crosses all bounds, she rids herself of all her hesitations and fears and transforms herself into Goddess Kali, the warrior.

text: Parvati, who was white-skinned (Gauri), naive, innocent and the tamer of Shiva morphs into Mahakali, who is bluish black-skinned (Kali), fierce, brave and is untamed by Shiva. She is armed with a scimitar, has her hair in a disarray and a garland of demon heads around her neck and an apron of demon arms around her waist.

text: As she descends upon the demon army, she destroys them by thousands, including Chand and Mund, earning herself the epithet of "Chamunda".

text: She advices the other Goddess to also give up their heaitations and learn to fight for themselves. She tells them that whenever mankind treats a woman less than anything she deserves, she has all the rights to turn into a Kali.

text: The goddesses Lakshmi, Saraswathi, Narsinghi, Aranyani and Aindri join her in battle assist her in destroying the demons. (A nod to the Saptamatrikas by the creators of the show)

text: The demon king then sends Rakthabija, a demon famous as being Mahakali's Primary enemy. He had the ability to create a clone of himself from every fallen drop of his blood.

text: Each time a goddess struck him, another Raktabija was born. Kali then licks up all the blood that oozes out of Raktabija's self and drains him completely of his pseudo-nectar, killing him.

text: She chops off the head of the first Raktajiba and runs amok on the battleground, murdering all those who came in her way.

text: To stop her rampage, Shiva awakens from his trance and lies down in front of Kali. She steps on him, realizes that she had stepped on her husband (which is a sin in Indian culture) and sticks out her tongue in shame.

text: Sad, Kali turns back into Parvati. Shiva makes her realize that she did nothing wrong, but Parvati is also bothered by the fact that Kali had to manifest in her and not any other woman at the time of need. She realizes that there is something more to her than just a housewife.

text: She embarks on a journey away from Kailash on the mission of self-realization, where she is introduced to Goddess Sati, her previous incarnation, by Shiva who acts as her guide. On the way, she meets Ambika/Durga, of whom she is a manifestation of.

text: The show goes on to introduce and tell the folklore of characters from Hindu Mythology like Sati, Bhadrakali, Kartikeya, Veerabhadra etc., and many demons like Tarakasura, Bhandasura, Daruka and more.

text: The story continues with her realizing her potential and that she is the Primordial Force (God) and leading to the death of the unrighteous (including Shumbh and Nishumbh).

text: The show will also feature the story of how Parvati killed and defeated Mahishasura and will be known to the world as Mahishasur Mardini.

text: Mahakali - Anth Hi Aarambh Hai traces this journey of how the humanly wife of lord Shiva, Parvati discovers her power and her existence as Adi Shakti of which she herself was unaware.

text: Cast[edit]

text:
Pooja Sharma as Parvati / Mahakali / Sapta Matrika / Ambika / Sati / Tripura Sundari / Matsya Parvati
Saurabh Raj Jain as Lord Shiva / Virabhadra / Unmata Bhairava
Falaq Naaz as Goddess Saraswati and Brahmani
Kanan Malhotra as Lord Vishnu
Nikita Sharma as Goddess Lakshmi and Vaishnavi[disambiguation needed] (Narayani)
Meghan Jadhav as Lord Kartikeya
Arjit Lavania / Abhishek Avasthi as Nandi[disambiguation needed]
Gagan Kang / Manish Bishla as Lord Indra
Nirbhay Wadhwa as Mahishasura
Abhaas Mehta as Shumbha (demon)
Danish Akhtar Saifi / Varun Pandey as Nishumbha (demon)
Rimpi Das as Ganga
Hitanshu Jinsi as Lord Vayu
Kunwar Pratham as Lord Chandra
Arjun as Lord Surya
Jai Harsh Vardhan as Lord Varuna
Vartika Chauhan as Goddess Indrani
Iti Kaurav as Aranyani
Hemany Verma as Tulasi
Deepak Jethi as Prajapati Daksha
Sampada Vaze as Prasuti
Sneha Namanandi as Daruka
Pranav Sahai as Darukasura (demon)
Vinita Joshi as Rati Goddess of Lust
Rohit Bakshi as Kama God of Love / Bhandasura (demon)
Joy Mathur as Tarakasura demon
Sagar Saikia as Raktabija (demon)

text: Reception[edit]

text: The show gained impressive and amazing trp ratings within only two weeks of airing and it came as a shock as it was very unexpected that Mahakali would gained such trps.

text: According to India Forums: Another new entrant makes it to the top 5 right away. Colors much-awaited show, Mahakaali: Anth Hi Aarambh Hai did not disappoint and while it has been receiving rave reviews, it has also garnered the numbers. The show went on to collect an amazing 2.9 points entering the list at the 3rd spot.

text: Mahakali - Anth Hi Aarambh Hai also grabbed the 1st position in the top 10 Fiction Shows in Hindi GEC of BARC trp ratings with 2.7 TVRs.

text: The show became the no 1 show across India.


document_title: Optical disc drive

question_text: what type of laser is used in cd and dvd players

root

text: Optical disc drive

text: History[edit]

text: This section needs expansion with: DVD history. You can help by adding to it. (December 2016)

tag: table

text: The first laser disc, demonstrated in 1972, was the Laservision 12-inch video disc. The video signal was stored as an analog format like a video cassette. The first digitally recorded optical disc was a 5-inch audio compact disc (CD) in a read-only format created by Sony and Philips in 1975.[1]

tag: p

text: The first erasable optical disc drives were announced in 1983, by Matsushita (Panasonic),[2] Sony, and Kokusai Denshin Denwa (KDDI).[3] Sony eventually released the first commercial erasable and rewritable 5.25-inch optical disc drive in 1987,[1] with dual-sided discs capable of holding 325 MB per side.[4]

text: The CD-ROM format was developed by Sony and Denon, introduced in 1984, as an extension of Compact Disc Digital Audio and adapted to hold any form of digital data. The CD-ROM format has a storage capacity of 650 MB. Also in 1984, Sony introduced a LaserDisc data storage format, with a larger data capacity of 3.28 GB.[5] The DVD format, developed by Panasonic, Sony, and Toshiba, was released in 1995, and was capable of holding 4.7 GB per layer.

text: The first Blu-Ray prototype was unveiled by Sony in October 2000,[6] and the first commercial recording device was released to market on April 10, 2003.[7] In January 2005, TDK announced that they had developed an ultra-hard yet very thin polymer coating ("Durabis") for Blu-ray discs; this was a significant technical advance because better protection was desired for the consumer market to protect bare discs against scratching and damage compared to DVD. Technically Blu-ray Disc also required a thinner layer for the narrower beam and shorter wavelength 'blue' laser.[8] The first BD-ROM players (Samsung BD-P1000) were shipped in mid-June 2006.[9] The first Blu-ray Disc titles were released by Sony and MGM on June 20, 2006.[10] The first mass-market Blu-ray Disc rewritable drive for the PC was the BWU-100A, released by Sony on July 18, 2006.[11]

text: Key components[edit]

text: Laser and optics[edit]

text: The most important  part of an optical disc drive is an optical path, placed in a pickup head (PUH),[12] usually consisting of a semiconductor laser, a lens for focusing the laser beam, and photodiodes  for detecting the light reflected from the disc's surface.[13]

text: Initially, CD-type lasers with a wavelength of 780 nm (within the infrared) were used. For DVDs, the wavelength was reduced to 650 nm (red color), and for Blu-ray Disc this was reduced even further to 405 nm (violet color).

text: Two main servomechanisms are used, the first to maintain the proper distance between lens and disc, to ensure the laser beam is focused as a small laser spot on the disc. The second servo moves the pickup head along the disc's radius, keeping the beam on the track, a continuous spiral data path. Optical disc media are 'read' beginning at the inner radius to the outer edge.

text: On read only media (ROM), during the manufacturing process the tracks are formed by pressing a thermoplastic resin into a glass 'master' with raised 'bumps' on a flat surface, creating pits and lands in the plastic disk. Because the depth of the pits is approximately one-quarter to one-sixth of the laser's wavelength, the reflected beam's phase is shifted in relation to the incoming beam, causing mutual destructive interference and reducing the reflected beam's intensity. This is detected by photodiodes that create corresponding electrical signals.

text: An optical disk recorder encodes (also known as burning) data onto a recordable CD-R, DVD-R, DVD+R, or BD-R disc (called a blank) by selectively heating parts of an organic dye layer with a laser.[citation needed]  This changes the reflectivity of the dye, thereby creating marks that can be read like the pits and lands on pressed discs. For recordable discs, the process is permanent and the media can be written to only once. While the reading laser is usually not stronger than 5 mW, the writing laser is considerably more powerful. The higher the writing speed, the less time a laser has to heat a point on the media, thus its power has to increase proportionally. DVD burners' lasers often peak at about 200 mW, either in continuous wave and pulses, although some have been driven up to 400 mW before the diode fails.

text: For rewritable CD-RW, DVD-RW, DVD+RW, DVD-RAM, or BD-RE media, the laser is used to melt a crystalline metal alloy in the recording layer of the disc.  Depending on the amount of power applied, the substance may be allowed to melt back (change the phase back) into crystalline form or left in an amorphous form, enabling marks of varying reflectivity to be created.

text: Double-sided media may be used, but they are not easily accessed with a standard drive, as they must be physically turned over to access the data on the other side.

text: Double layer (DL) media have two independent data layers separated by a semi-reflective layer. Both layers are accessible from the same side, but require the optics to change the laser's focus. Traditional single layer (SL) writable media are produced with a spiral groove molded in the protective polycarbonate layer (not in the data recording layer), to lead and synchronize the speed of recording head. Double-layered writable media have: a first polycarbonate layer with a (shallow) groove, a first data layer, a semi-reflective layer, a second (spacer) polycarbonate layer with another (deep) groove, and a second data layer. The first groove spiral usually starts on the inner edge and extends outwards, while the second groove starts on the outer edge and extends inwards.[14][15]

text: Some drives support Hewlett-Packard's LightScribe photothermal printing technology for labeling specially coated discs.

text: Rotational mechanism[edit]

text: The rotational mechanism in an optical drive differs considerably from that of a hard disk drive's, in that the latter keeps a constant angular velocity (CAV), in other words a constant number of revolutions per minute (RPM). With CAV, a higher throughput is generally achievable at the outer disc compared to the inner.

text: On the other hand, optical drives were developed with an assumption of achieving a constant throughput, in CD drives initially equal to 150 KiB/s. It was a feature important for streaming audio data that always tend to require a constant bit rate. But to ensure no disc capacity was wasted, a head had to transfer data at a maximum linear rate at all times too, without slowing on the outer rim of disc. This led to optical drives—until recently—operating with a constant linear velocity (CLV). The spiral groove of the disc passed under its head at a constant speed. The implication of CLV, as opposed to CAV, is that disc angular velocity is no longer constant, and the spindle motor needed to be designed to vary its speed from between 200 RPM on the outer rim and 500 RPM on the inner.

text: Later CD drives kept the CLV paradigm, but evolved to achieve higher rotational speeds, popularly described in multiples of a base speed. As a result, a 4× drive, for instance, would rotate at 800-2000 RPM, while transferring data steadily at 600 KiB/s, which is equal to 4 × 150 KiB/s.

text: For DVDs, base or 1× speed is 1.385 MB/s, equal to 1.32 MiB/s, approximately nine times faster than the CD base speed. For Blu-ray drives, base speed is 6.74 MB/s, equal to 6.43 MiB/s.

text: Because keeping a constant transfer rate for the whole disc is not so important in most contemporary CD uses, a pure CLV approach had to be abandoned to keep the rotational speed of the disc safely low while maximizing data rate. Some drives work in a partial CLV (PCLV) scheme, by switching from CLV to CAV only when a rotational limit is reached. But switching to CAV requires considerable changes in hardware design, so instead most drives use the zoned constant linear velocity (Z-CLV) scheme. This divides the disc into several zones, each having its own constant linear velocity. A Z-CLV recorder rated at "52×", for example, would write at 20× on the innermost zone and then progressively increase the speed in several discrete steps up to 52× at the outer rim. Without higher rotational speeds, increased read performance may be attainable by simultaneously reading more than one point of a data groove,[16] but drives with such mechanisms are more expensive, less compatible, and very uncommon.

text: Limit[edit]

text: Both DVDs and CDs have been known to explode [17] when damaged or spun at excessive speed. This imposes a constraint on the maximum speed (56× for CDs or around 18× in the case of DVDs) at which drives can operate.

text: Loading mechanisms[edit]

text: Current optical drives use either a tray-loading mechanism, where the disc is loaded onto a motorized or manually operated tray, or a slot-loading mechanism, where the disc is slid into a slot and drawn in by motorized rollers.  With both types of mechanism, if a CD or DVD is left in the drive after the computer is turned off, the disc cannot be ejected using the normal eject mechanism of the drive.  However, tray-loading drives account for this situation by providing a small hole where one can insert a straightened paperclip to manually open the drive tray to retrieve the disc.  Slot-loading optical disc drives have the disadvantages that they cannot usually accept the smaller 80 mm discs (unless 80 mm optical disc adapter is used) or any non-standard sizes, usually have no emergency eject hole or eject button, and therefore have to be disassembled if the optical disc cannot be ejected normally.  However, the Nintendo Wii, because of backward compatibility with Nintendo GameCube games,[18] and PlayStation 3[19] video game consoles are able to load standard size DVDs and 80 mm discs in the same slot-loading drive.

text: A small number of drive models, mostly compact portable units, have a top-loading mechanism where the drive lid is opened upwards and the disc is placed directly onto the spindle[20] (for example, all PlayStation One consoles, portable CD players, and some standalone CD recorders all feature top-loading drives). These sometimes have the advantage of using spring-loaded ball bearings to hold the disc in place, minimizing damage to the disc if the drive is moved while it is spun up.

text: Some early CD-ROM drives used a mechanism where CDs had to be inserted into special cartridges or caddies, somewhat similar in appearance to a 3.5" floppy diskette. This was intended to protect the disc from accidental damage by enclosing it in a tougher plastic casing, but did not gain wide acceptance due to the additional cost and compatibility concerns—such drives would also inconveniently require "bare" discs to be manually inserted into an openable caddy before use.  Ultra Density Optical and Universal Media Disc use optical disc cartridges.

text: There were also some early CD-ROM drives for desktop PCs in which its tray-loading mechanism will eject slightly and user has to pull out the tray manually to load CD, similar to the tray ejecting method used in internal optical disc drives of modern laptops and modern external slim portable optical disc drives. Like the top-loading mechanism, they have spring-loaded ball bearings on the spindle.

text: Computer interfaces[edit]

text: Most internal drives for personal computers, servers and workstations are designed to fit in a standard 5.25" drive bay and connect to their host via an ATA or SATA interface. Additionally, there may be digital and analog outputs for audio. The outputs may be connected via a header cable to the sound card or the motherboard. At one time, computer software resembling CD players  controlled playback of the CD. Today the information is extracted from the disc as data, to be played back or converted to other file formats.

text: External drives usually have USB or FireWire interfaces.  Some portable versions for laptops power themselves from batteries or directly from their interface bus.

text: Drives with SCSI interface were made, but they are less common and tend to be more expensive, because of the cost of their interface chipsets, more complex SCSI connectors, and small volume of sales.

text: When the optical disc drive was first developed, it was not easy to add to computer systems. Some computers such as the IBM PS/2 were standardizing on the 3.5" floppy and 3.5" hard disk, and did not include a place for a large internal device. Also IBM PCs and clones at first only included a single (parallel) ATA drive interface, which by the time the CDROM was introduced, was already being used to support two hard drives. Early laptops simply had no built-in high-speed interface for supporting an external storage device.

text: This was solved through several techniques:

text:
Early sound cards could include a CD-ROM drive interface.  Initially, such interfaces were proprietary to each CD-ROM manufacturer.  A sound card could often have two or three different interfaces which are able to communicate with cdrom drive.
A parallel port external drive was developed that connected between a printer and the computer. This was slow but an option for laptops.
A PCMCIA optical drive interface was also developed for laptops.
A SCSI card could be installed in desktop PCs for an external SCSI drive enclosure, though SCSI was typically much more expensive than other options.

tag: ul

text: Internal mechanism of a drive[edit]

text: The optical drives in the photos are shown right side up; the disc would sit on top of them. The laser and optical system scans the underside of the disc.

text: With reference to the top photo, just to the right of image center is the disc motor, a metal cylinder, with a gray centering hub and black rubber drive ring on top. There is a disc-shaped round clamp, loosely held inside the cover and free to rotate; it's not in the photo. After the disc tray stops moving inward, as the motor and its attached parts rise, a magnet near the top of the rotating assembly contacts and strongly attracts the clamp to hold and center the disc. This motor is an "outrunner"-style brushless DC motor which has an external rotor – every visible part of it spins.

text: Two parallel guide rods that run between upper left and lower right in the photo carry the "sled", the moving optical read-write head. As shown, this "sled" is close to, or at the position where it reads or writes at the edge of the disc. To move the "sled" during continuous read or write operations, a stepper motor rotates a leadscrew to move the "sled" throughout its total travel range. The motor, itself, is the short gray cylinder just to the left of the most-distant shock mount; its shaft is parallel to the support rods. The leadscrew is the rod with evenly-spaced darker details; these are the helical grooves that engage a pin on the "sled".

text: In contrast, the mechanism shown in the second photo, which comes from a cheaply made DVD player, uses less accurate and less efficient brushed DC motors to both move the sled and spin the disc. Some older drives use a DC motor to move the sled, but also have a magnetic rotary encoder to keep track of the position. Most drives in computers use stepper motors.

text: The gray metal chassis is shock-mounted at its four corners to reduce sensitivity to external shocks, and to reduce drive noise from residual imbalance when running fast. The soft shock mount grommets are just below the brass-colored screws at the four corners (the left one is obscured).

text: In the third photo, the components under the cover of the lens mechanism are visible. The two permanent magnets on either side of the lens holder as well as the coils that move the lens can be seen. This allows the lens to be moved up, down, forwards, and backwards to stabilize the focus of the beam.

text: In the fourth photo, the inside of the optics package can be seen. Note that since this is a CD-ROM drive, there is only one laser, which is the black component mounted to the bottom left of the assembly. Just above the laser are the first focusing lens and prism that direct the beam at the disc. The tall, thin object in the center is a half-silvered mirror that splits the laser beam in multiple directions. To the bottom right of the mirror is the main photodiode that senses the beam reflected off the disc. Above the main photodiode is a second photodiode that is used to sense and regulate the power of the laser.

text: The irregular orange material is flexible etched copper foil supported by thin sheet plastic; these are "flexible printed circuits" that connect everything to the electronics (which is not shown).

text: Compatibility[edit]

text: Most optical drives are backward compatible with their ancestors up to CD, although this is not required by standards.

text: Compared to a CD's 1.2 mm layer of polycarbonate, a DVD's laser beam only has to penetrate 0.6 mm in order to reach the recording surface. This allows a DVD drive to focus the beam on a smaller spot size and to read smaller pits. DVD lens supports a different focus for CD or DVD media with same laser.  With the newer Blu-ray disc drives, the laser only has to penetrate 0.1 mm of material.  Thus the optical assembly would normally have to have an even greater focus range.  In practice, the Blu-ray optical system is separate from the DVD/CD system.

text:
Optical disc drive

Optical disc or optical media

Pressed CD

CD-R

CD-RW

Pressed DVD

DVD-R

DVD+R

DVD-RW

DVD+RW

DVD+R DL

Pressed CAT BD

BD-R

BD-RE

BD-R DL

BD-RE DL

Audio CD player

Read

Read 1

Read 2

None

None

None

None

None

None

None

None

None

None

None

CD-ROM drive

Read

Read 1

Read 2

None

None

None

None

None

None

None

None

None

None

None

CD-R recorder

Read

Write

Read

None

None

None

None

None

None

None

None

None

None

None

CD-RW recorder

Read

Write

Write

None

None

None

None

None

None

None

None

None

None

None

DVD-ROM drive

Read

Read 3

Read 3

Read

Read 4

Read 4

Read 4

Read 4

Read 5

None

None

None

None

None

DVD-R recorder

Read

Write

Write

Read

Write

Read 6

Read

Read 6

Read 5

None

None

None

None

None

DVD-RW recorder

Read

Write

Write

Read

Write

Read 7

Write 8

Read 6

Read 5

None

None

None

None

None

DVD+RW recorder

Read

Write

Write

Read

Read 6

Read 9

Read 6

Write

Read 5

None

None

None

None

None

DVD+R recorder

Read

Write

Write

Read

Read 6

Write

Read 6

Write

Read 5

None

None

None

None

None

DVD±RW recorder

Read

Write

Write

Read

Write

Write

Write

Write

Read 5

None

None

None

None

None

DVD±RW/DVD+R DL recorder

Read

Write

Write

Read

Write 10

Write

Write 10

Write

Write

None

None

None

None

None

BD-ROM

Read

Read

Read

Read

Read

Read

Read

Read

Read

Read

Read

Read

Read

Read

BD-R recorder

Read  11

Write 11

Write 11

Read

Write

Write

Write

Write

Write

Read

Write

Read

Read

Read

BD-RE recorder

Read  11

Write 11

Write 11

Read

Write

Write

Write

Write

Write

Read

Write

Write

Read

Read

BD-R DL recorder

Read  11

Write 11

Write 11

Read

Write

Write

Write

Write

Write

Read

Write

Read

Write

Read

BD-RE DL recorder

Read  11

Write 11

Write 11

Read

Write

Write

Write

Write

Write

Read

Write

Write

Write

Write

text:
^1  Some types of CD-R media with less-reflective dyes may cause problems.
^2  May not work in non MultiRead-compliant drives.
^3 May not work in some early-model DVD-ROM drives.  CD-R would not work in any drive that did not have a 780 nm laser.  CD-RW compatibility varied.
^4  DVD+RW discs did not work in early video players that played DVD-RW discs.  This was not due to any incompatibility with the format but was a deliberate feature built into the firmware by one drive manufacturer.
^5  Read compatibility with existing DVD drives may vary greatly with the brand of DVD+R DL media used.  Also drives that predated the media did not have the book code for DVD+R DL media in their firmware (this was not an issue for DVD-R DL though some drives could only read the first layer).
^6  Early DVD+RW and DVD+R recorders could not write to DVD-R(W) media (and vice versa).
^7  Will work in all drives that read DVD-R as compatibility ID byte is the same.
^8  Recorder firmware may blacklist or otherwise refuse to record to some brands of DVD-RW media.
^9  DVD+RW format was released before DVD+R.  All DVD+RW only drives could be upgraded to write DVD+R discs by a firmware upgrade.
^10  As of April 2005, all DVD+R DL recorders on the market are Super Multi-capable.
^11  As of October 2006, recently released BD drives are able to read and write CD media.

text: Recording performance[edit]

text: During the times of CD writer drives, they are often marked with three different speed ratings. In these cases, the first speed is for write-once (R) operations, the second speed for re-write (RW) operations, and the last speed for read-only (ROM) operations. For example, a 40×/16×/48× CD writer drive is capable of writing to CD-R media at speed of 40× (6,000 KB/s), writing to CD-RW media at speed of 16× (2,400 KB/s), and reading from a CD-ROM media at speed of 48× (7,200 KB/s).

text: During the times of combo (CD-RW/DVD-ROM) drives, an additional speed rating (e.g. the 16× in 52×/32×/52×/16×) is designated for DVD-ROM media reading operations.

text: For DVD writer drives, Blu-ray disc combo drives, and Blu-ray disc writer drives, the writing and reading speed of their respective optical media are specified in its retail box, user's manual, or bundled brochures or pamphlets.

text: In the late 1990s, buffer underruns became a very common problem as high-speed CD recorders began to appear in home and office computers, which—for a variety of reasons—often could not muster the I/O performance to keep the data stream to the recorder steadily fed.  The recorder, should it run short, would be forced to halt the recording process, leaving a truncated track that usually renders the disc useless.

text: In response, manufacturers of CD recorders began shipping drives with "buffer underrun protection" (under various trade names, such as Sanyo's "BURN-Proof", Ricoh's "JustLink" and Yamaha's "Lossless Link"). These can suspend and resume the recording process in such a way that the gap the stoppage produces can be dealt with by the error-correcting logic built into CD players and CD-ROM drives.  The first of these drives were rated at 12× and 16×.

text: While drives are burning DVD+R, DVD+RW and all Blu-ray formats, they do not require any such error correcting recovery as the recorder is able to place the new data exactly on the end of the suspended write effectively producing a continuous track (this is what the DVD+ technology achieved).  Although later interfaces were able to stream data at the required speed, many drives now write in a 'zoned constant linear velocity'.  This means that the drive has to temporarily suspend the write operation while it changes speed and then recommence it once the new speed is attained.  This is handled in the same manner as a buffer underrun.

text: The internal buffer of optical disc writer drives is: 8 MiB or 4 MiB when recording BD-R, BD-R DL, BD-RE, or BD-RE DL media; 2 MiB when recording DVD-R, DVD-RW, DVD-R DL, DVD+R, DVD+RW, DVD+RW DL, DVD-RAM, CD-R, or CD-RW media.

text: Recording schemes[edit]

text: CD recording on personal computers was originally a batch-oriented task in that it required specialised authoring software to create an "image" of the data to record, and to record it to disc in the one session.  This was acceptable for archival purposes, but limited the general convenience of CD-R and CD-RW discs as a removable storage medium.

text: Packet writing is a scheme in which the recorder writes incrementally to disc in short bursts, or packets. Sequential packet writing fills the disc with packets from bottom up. To make it readable in CD-ROM and DVD-ROM drives, the disc can be closed at any time by writing a final table-of-contents to the start of the disc; thereafter, the disc cannot be packet-written any further. Packet writing, together with support from the operating system and a file system like UDF, can be used to mimic random write-access as in media like flash memory and magnetic disks.

text: Fixed-length packet writing (on CD-RW and DVD-RW media) divides up the disc into padded, fixed-size packets. The padding reduces the capacity of the disc, but allows the recorder to start and stop recording on an individual packet without affecting its neighbours.  These resemble the block-writable access offered by magnetic media closely enough that many conventional file systems will work as-is.  Such discs, however, are not readable in most CD-ROM and DVD-ROM drives or on most operating systems without additional third-party drivers.  The division into packets is not as reliable as it may seem as CD-R(W) and DVD-R(W) drives can only locate data to within a data block.  Although generous gaps (the padding referred to above) are left between blocks, the drive nevertheless can occasionally miss and either destroy some existing data or even render the disc unreadable.

text: The DVD+RW disc format eliminates this unreliability by embedding more accurate timing hints in the data groove of the disc and allowing individual data blocks (or even bytes) to be replaced without affecting backward compatibility (a feature dubbed "lossless linking"). The format itself was designed to deal with discontinuous recording because it was expected to be widely used in digital video recorders.  Many such DVRs use variable-rate video compression schemes which require them to record in short bursts; some allow simultaneous playback and recording by alternating quickly between recording to the tail of the disc whilst reading from elsewhere.  The Blu-ray disc system also encompasses this technology.

text: Mount Rainier aims to make packet-written CD-RW and DVD+RW discs as convenient to use as that of removable magnetic media by having the firmware format new discs in the background and manage media defects (by automatically mapping parts of the disc which have been worn out by erase cycles to reserve space elsewhere on the disc).  As of February 2007, support for Mount Rainier is natively supported in Windows Vista.  All previous versions of Windows require a third-party solution, as does Mac OS X.

text: Recorder Unique Identifier[edit]

text: Owing to pressure from the music industry, as represented by the IFPI and RIAA, Philips developed the Recorder Identification Code (RID) to allow media to be uniquely associated with the recorder that has written it. This standard is contained in the Rainbow Books. The RID-Code consists of a supplier code (e.g. "PHI" for Philips), a model number and the unique ID of the recorder. Quoting Philips, the RID "enables a trace for each disc back to the exact machine on which it was made using coded information in the recording itself. The use of the RID code is mandatory."[21]

text: Although the RID was introduced for music and video industry purposes, the RID is included on every disc written by every drive, including data and backup discs.  The value of the RID is questionable as it is (currently) impossible to locate any individual recorder due to there being no database.

text: Source IDentification Code[edit]

text: The Source IDentification Code (SID) is an eight character supplier code that is placed on optical discs by the manufacturer. The SID identifies not only manufacturer, but also the individual factory and machine that produced the disc.

text: According to Phillips, the administrator of the SID codes, the SID code provides an optical disc production facility with the means to identify all discs mastered or replicated in its plant, including the specific Laser Beam Recorder (LBR) signal processor or mould that produced a particular stamper or disc.[21]

text: Use of RID and SID together in forensics[edit]

text: The standard use of RID and SID mean that each disc written contains a record of the machine that produced a disc (the SID), and which drive wrote it (the RID). This combined knowledge may be very useful to law enforcement, to investigative agencies, and to private or corporate investigators.[22]


document_title: U.S. history of alcohol minimum purchase age by state

question_text: when did illinois raise the drinking age to 21

text: The alcohol laws of the United States regarding minimum age for purchase have changed over time. The history is given in the table below. Unless otherwise noted, if different alcohol categories have different minimum purchase ages, the age listed below is set at the lowest age given (e.g. if the purchase age is 18 for beer and 21 for wine or spirits, as was the case in several states, the age in the table will read as "18", not "21"). In addition, the purchase age is not necessarily the same as the minimum age for consumption of alcoholic beverages, although they have often been the same.

text: As one can see in the table below, there has been much volatility in the states' drinking ages since the repeal of Prohibition in 1933. Shortly after the ratification of the 21st amendment in December, most states set their purchase ages at 21 since that was the Voting age at the time. Most of these limits remained constant until the early 1970s. From 1969 to 1976, some 30 states lowered their purchase ages, generally to 18. This was primarily because the voting age was lowered from 21 to 18 in 1971 with the 26th amendment. A lot of states started to lower their minimum drinking age in response, most of this occurring in 1972 or 1973.[1][2][3] Twelve states kept their purchase ages at 21 since repeal of Prohibition and never changed them.

text: From 1976 to 1983, several states voluntarily raised their purchase ages to 19 (or, less commonly, 20 or 21), in part to combat drunk driving fatalities.[citation needed] In 1984, Congress passed the National Minimum Drinking Age Act, which required states to raise their ages for purchase and public possession to 21 by October 1986 or lose 10% of their federal highway funds. By mid-1988, all 50 states and the District of Columbia had raised their purchase ages to 21 (but not Puerto Rico, Guam, or the Virgin Islands, see Additional Notes below). South Dakota and Wyoming were the final two states to comply with the age 21 mandate. The current drinking age of 21 remains a point of contention among many Americans, because of it being higher than the age of majority (18 in most states) and higher than the drinking ages of most other countries. The National Minimum Drinking Age Act is also seen as a congressional sidestep of the tenth amendment. Although debates have not been highly publicized, a few states have proposed legislation to lower their drinking age,[4] while Guam has raised its drinking age to 21 in July 2010.[5]

text:
State
Pre-Prohibition
(prior to 1919)
Post-Prohibition
(after 1933)
1970s / 26th Amendment
(adopted in 1971)
1980s /
Drinking Age Act of 1984
21st century

Alabama
Pre 1881:
None
1881:
21 (none with consent of parent)[6]
21
1970:
Lowered to 19[7]
1986:
Raised to 21[8]
21 (no one underage is allowed consumption Section 28-1)

Alaska
 ?
21[7]
1970:
Lowered to 19[9]
1984:
Raised to 21 with grandfather clause (if born before January 1, 1965)[10][11]
21

Arizona
 ?
21[11]
1972:
Lowered to 19[12][13]
1985:
Raised to 21[8]
21

Arkansas
Pre 1925:
None[7]
1925:
21[7]
21
21[14]
21 [8]
21

California
Pre 1891:
Regulated by municipality/county (common age was 16)[15][16][17]
1891:
18 (statewide)[18]
1933:
21[7]
21
21 [8]
21 (except small amounts for religious ceremonies)

Colorado
None[11]
1945:
18: for beer
21: for wine and liquor[7]
18 [19]
Raised to 21 in 1987 [8]
21

Connecticut
 ?
21 [11]
1972:
Lowered to 18[20]
1982:
Raised to 19
1983:
Raised to 20
1985:
Raised to 21[21]
21 (exemptions: (1) a person over age eighteen who is an employee or permit holder under section 30-90a and who possesses alcoholic liquor in the course of such person’s employment or business, (2) a minor who possesses alcoholic liquor on the order of a practicing physician, or (3) a minor who possesses alcoholic liquor while accompanied by a parent, guardian or spouse of the minor, who has attained the age of twenty-one. Nothing in this subsection shall be construed to burden a person’s exercise of religion under section 3 of article first of the Constitution of the state in violation of subsection (a) of section 52-571b.[22]

Delaware
 ?
21 [11]
1972:
Lowered to 20[13]
1984:
Raised to 21[8]
21

District of Columbia
 ?
18: for beer and wine[11]
21: for liquor[23][24]
18: for beer and wine[13][24]
21: for liquor
1986:
Raised to 21 with grandfather clause.[25][26]
21

Florida
 ?
18[7]
1972:
19 [27]
1985:
Raised to 21 with grandfather clause [27]
21 [28]

Georgia
 ?
21 [11]
1972:
Lowered to 18[12]
1984:
Raised to 19[14]
1985:
Raised to 20[14]
1986:
Raised to 21[14]
21

Hawaii
 ?
21[7]
1972:
Lowered to 18[13]
1986:
Raised to 21[8]
21

Idaho
 ?
20: for beer[29][30]
21: for wine and liquor[11][31]
1972:
Lowered to 19 (all)[13][32]
1987:
Raised to 21 in 1987 (Apr 11) with grandfather clause[8][33]
21

Illinois
1872:
Age of majority
(none with written consent of parent)[34]
pre 1961: Age of majority 1961: Raised to 21 [35]
1973:
Lowered to 19: for beer and wine
21: for liquor[36]
1980:
Raised to 21[37]
21

Indiana
 ?
Post-1934:
21[7]
21[14]
21[8]
21

Iowa
 ?
21[7]
1972:
Lowered to 19 in 1972 (Jul 1)
1973:
Lowered to 18 in 1973 (Jul 1)
1978:
Raised to 19 in 1978 (Jul 1)[38]
1986:
Raised to 21 in 1986 (Jul 1) with grandfather clause.[14][38]
21

Kansas
 ?
1949:
18: for beer and wine with less than 4% ABV
21: for liquor[7]
18: for beer and wine with less than 4% ABV[14]
21: for beer and wine with 4% ABV or more[14]
21: for liquor[14][19]
1985:
Raised to 21[8]
21 (However, anyone under 21 may consume cereal malt beverages with parental supervision on their own property)

Kentucky
 ?
1938:
21[7]
21[14]
21[8]
21

Louisiana
 ?
As of 1948:
18[13]
18[19]
1987:
Raised to 21 de jure in 1987,[8]
but de facto age was still 18 until 1995 due to a sale loophole.
1995:
De facto age raised to 21 in 1995 when loophole was closed.[39]
1996:
In 1996, briefly lowered by Louisiana Supreme Court to 18 until it reversed its decision, raising to 21 three months later.[40]
Other exceptions still remain.[41]
21

Maine
 ?
21[7]
1969:
Lowered to 20
1972:
Lowered to 18[12]
1977:
Raised to 20[8][42]
1985:
Raised to 21[8]
21

Maryland
 ?
21[7]
1974:
Lowered to 18: for beer and wine
21: for liquor[43][44]
1982:
Raised to 21 with grandfather clause [8][45]
21 (however anyone can drink when parents, spouses, teachers are present)

Massachusetts
 ?
21 [11]
1973:
Lowered to 18
1979:
Raised to 20 in 1979 (Apr 16)[46][47][48]
Raised to 21 in 1985 [8]
21

Michigan
 ?
21[7]
1972:
Lowered to 18 in 1972 (Jan 1)[49]
1978:
Raised to 19 in 1978 (Dec 3)[50][51]
1978:
Raised to 21 in 1978 (Dec 21), 18 days later.[8]
First state to raise age to 21 since it was lowered
21

Minnesota
 ?
21 [11]
1973:
Lowered to 18
1976:
Raised to 19[52]
First state to raise age after lowering.
1986:
Raised to 21[53]
21

Mississippi
 ?
1966:
18: for beer and wine
21: for liquor[7]
(alcohol not legalized until 1966)
18[19]
Raised to 21 in 1986 [8]
21

Missouri
 ?
1945:
21[7]
21
21 [8]
21

Montana
 ?
21 [11]
1971:
Lowered to 19[54]
1973:
Lowered to 18[55][56]
1979:
Raised to 19
1987:
Raised to 21[8][57]
21

Nebraska
 ?
21[58]
1969:
Lowered to 20
1972:
Lowered to 19[58]
1980:
Raised to 20[14]
1985:
Raised to 21[14]
21

Nevada
 ?
1933:
21[7]
21
21[8]
21

New Hampshire
 ?
21[11]
1973:
Lowered to 18[59]
1979:
Raised to 20
1985:
Raised to 21[8][21]
21

New Jersey
Before 1880:
None
Post-1880:
18 (penalties only against businesses)[60][61][62]
21[citation needed]
1973:
Lowered to 18 [12]
1980:
Raised to 19
1983:
Raised to 21[8][63]
21

New Mexico
 ?
1934:
21[7]
21[14]
21[8]
21

New York
21
18[64]
18
1982:
Raised to 19 in 1982 (Dec)
1985:
Raised to 21 in 1985 (Dec)[21][65][66]
21

North Carolina
 ?
18[11]
18: for beer and wine[19]
21: for liquor
1983:
19: for beer and wine
21: for liquor
1986:
Raised to 21 in 1986 (Sep 1)[8][26]
21

North Dakota
 ?
1936:
21[7]
21[14]
21 [67]
21

Ohio
 ?
1935:
18: for 3.2% ABW beer
21: for beer stronger than 3.2% ABW, wine and liquor[68]
18: for 3.2% ABW beer
21: for beer stronger than 3.2% ABW, wine and liquor
1982 (Aug. 19 to Oct. 1):
19: for 3.2% ABW beer[14]
21: for beer stronger than 3.2% ABW, wine and liquor[14]
1982 (From Oct. 1):
19: beer
21: wine and liquor[69]
1988:
21[14]
21 (However, anyone can drink with parents or legal-age spouse)

Oklahoma
 ?
Men:
21
Women:
18: 3.2% ABW beer
21: for beer stronger than 3.2% ABW, wine and liquor[70]
1976:
Lowered to 18 (for 3.2% ABW beer) for both sexes in 1976 (Dec) [71]
Last state to lower the drinking age.
1983:
Raised to 21[11][72]
21

Oregon
 ?
1933:
21[7]
21
21 [8]
21

Pennsylvania
 ?
1935:
21[7]
21
21 [8][51]
21

Rhode Island
 ?
21[11]
1970:
Lowered to 18[12][73]
1980:
Raised to 19
1981:
Raised to 20
1984:
Raised to 21[21]
21

South Carolina
21[74]
1935:
18: for beer and wine
21: for liquor[7]
18: for beer and wine[19]
21: for liquor
1984:
19: for beer and wine[7]
21: for liquor
1986:
Raised to 21[8]
21

South Dakota
 ?
1934:
21 (all)
1939:
Lowered to 18: for 3.2% beer
Raised to 19: for 3.2% beer[75]
1972:
18: for beer and wine
21: for liquor[13]
1984:
19: for beer and wine
21: for liquor[8]
1988:
Raised to 21[57]
21

Tennessee
Pre 1881:
None
1881:
21[76]
21[7]
1964:
Lowered to 18[7]
1979:
Raised to 19
1984:
Raised to 21[8]
21

Texas
Pre 1909:
21
None (with written permission of parent or guardian)
Post 1909:
21[77][78]
21[7]
1973:
Lowered to 18[79]
1981:
Raised to 19[80]
1986:
Raised to 21 in 1986 (Sep 1)[8][26]
21

Utah
 ?
1935:
21[7]
21[14]
21 [8]
21

Vermont
 ?
21[7]
1971:
Lowered to 18[81][82]
1986:
Raised to 21[21][82]
21

Virginia
 ?
21[83]
1974:
Lowered to 18: for beer and wine
(21: for liquor remained)[83]
1981:
Raised to 19 for off-premises consumption
1983:
Raised to 19 (all beer)
1985:
Raised to 21[83]
21

Washington
"Age of majority"
since 1877 [84]
21[citation needed]
21
21 [8]
21

West Virginia
 ?
18: for beer and wine
21: for liquor[11]
1972:
Lowered to 18 (all)[85]
1983:
Raised to 19
(& 21 for non-residents)[8][42]
1986:
Raised to 21[8]
21

Wisconsin
1839–1866:
18: for wine and liquor
None: for beer
Post-1866:
21 (all)[86]
18: for beer
21: for wine and spirits
1957:
21: for residents of bordering states with age limit 21.[87]
1963:
Raised to 21 (off-premises beer sales, remained 18 for on-premises).[87]
1972:
Lowered to 18 (all) in 1972 (Mar)[87]
1977:
Border state restriction lifted.[87]
1984:
Raised to 19
1986:
Raised to 21 (September 1, 1986)[87]
21 (however anyone can drink when parents, spouses, teachers are present)[citation needed]

Wyoming
 ?
21[7]
1973:
Lowered to 19[13]
1988:
Raised to 21 in 1988 (Jul 1)[88][89]
Last state to raise de jure drinking age to 21
21

American Samoa
 ?
 ?
 ?
21?
21 [90]

Northern Mariana Islands
–
–
 ?
21?
21 [91]

Puerto Rico
 ?
18
18
Kept at 18
despite 10% highway funding
penalty under Drinking Age Act.
18 [92]

Virgin Islands
 ?
 ?
 ?
18
18 [93]

Guam
 ?
21?
18
18
Raised to 21 in 2010 [5]

text: Additional notes[edit]

text:
Contrary to popular belief, since the National Minimum Drinking Age Act of 1984, not all states specifically prohibit minors' and young adults' consumption of alcohol in private settings. That is because the federal law is concerned only with purchase and public possession, not private consumption, and contains several exceptions. As of January 1, 2007, 14 states and the District of Columbia ban underage consumption outright, 19 states do not specifically ban underage consumption outright, and 17 states have family member or location exceptions to their underage consumption laws. Federal law explicitly provides for religious, medical, employment and private club possession exceptions; as of 2005, 31 states have family member or location exceptions to their underage possession laws.[41]
In the 1960s the age for buying or drinking beer and wine in the District of Columbia (Washington, D.C.) was 18; the age for hard liquor was 21.[23][24] Residents from Virginia and Maryland would often drive to D.C. to obtain alcohol. In Louisiana, the 1987 law raising the age from 18 to 21 was deliberately written solely to comply with the National Minimum Drinking Age Act of 1984 to avoid losing highway funding, while still allowing 18- to 20-year-olds to drink as before. Not only did it still allow 18- to 20-year-olds to consume in private, it contained a major loophole allowing bars and stores to sell alcohol to 18- to 20-year-olds without penalty (despite purchase being technically illegal) which meant that the de facto age was still 18.[39] In other words, the drinking age was 21 only on paper. This loophole was closed in 1995, but in 1996 the Louisiana Supreme Court declared a drinking age of 21 unconstitutional.[39] That briefly lowered the de jure purchase age to 18, causing an uproar which prompted the Louisiana Supreme Court to reverse its decision, raising the age to 21 three months later.[40] Other exceptions still remain to this day, including drinking in a private residence,[41] and Louisiana still has some of the most liberal general alcohol laws of any state.
Some states were "dry" well before national Prohibition was enacted in 1919, in some cases since achieving statehood. Also, some states did not become fully "wet" until several years after the repeal of Prohibition in 1933 (e.g. Mississippi in 1966). Since 1966, all states and territories of the USA have been "wet", but dry counties and towns still exist in some states.


document_title: Informed consent

question_text: where did the concept of informed consent originate

text: Informed consent

text: Assessment[edit]

text: Informed consent can be complex to evaluate, because neither expressions of consent, nor expressions of understanding of implications, necessarily mean that full adult consent was in fact given, nor that full comprehension of relevant issues is internally digested. Consent may be implied within the usual subtleties of human communication, rather than explicitly negotiated verbally or in writing. In some cases consent cannot legally be possible, even if the person protests he does indeed understand and wish. There are also structured instruments for evaluating capacity to give informed consent, although no ideal instrument presently exists.[citation needed]

text: Thus, there is always a degree to which informed consent must be assumed or inferred based upon observation, or knowledge, or legal reliance. This especially is the case in sexual or relational issues. In medical or formal circumstances, explicit agreement by means of signature—normally relied on legally—regardless of actual consent, is the norm. This is the case with certain procedures, such as a "do not resuscitate" directive that a patient signed prior to their illness.[citation needed]

text: Brief examples of each of the above:

text:
A person may verbally agree to something from fear, perceived social pressure, or psychological difficulty in asserting true feelings. The person requesting the action may honestly be unaware of this and believe the consent is genuine, and rely on it. Consent is expressed, but not internally given.
A person may claim to understand the implications of some action, as part of consent, but in fact has failed to appreciate the possible consequences fully and may later deny the validity of the consent for this reason. Understanding needed for informed consent is present but is, in fact (through ignorance), not present.
A person signs a legal release form for a medical procedure, and later feels he did not really consent. Unless he can show actual misinformation, the release is usually persuasive or conclusive in law, in that the clinician may rely legally upon it for consent. In formal circumstances, a written consent usually legally overrides later denial of informed consent (unless obtained by misrepresentation).
Informed consent in the U.S. can be overridden in emergency medical situations pursuant to 21CFR50.24, which was first brought to the general public's attention via the controversy surrounding the study of Polyheme.

tag: ol

text: Valid elements[edit]

text: For an individual to give valid informed consent, three components must be present: disclosure, capacity and voluntariness.[3][4]

text:
Disclosure requires the researcher to supply each prospective subject with the information necessary to make an autonomous decision and also to ensure that the subject adequate understands the information provided. This latter requirement implies that a written consent form be written in lay language suited for the comprehension skills of subject population, as well as assessing the level of understanding through conversation.
Capacity pertains to the ability of the subject to both understand the information provided and form a reasonable judgment based on the potential consequences of his/her decision.
Voluntariness refers to the subject’s right to freely exercise his/her decision making without being subjected to external pressure such as coercion, manipulation, or undue influence.

text: Waiver of requirement[edit]

text: Waiver of the consent requirement may be applied in certain circumstances where no foreseeable harm is expected to result from the study or when permitted by law, federal regulations, or if an ethical review committee has approved the non-disclosure of certain information.[5]

text: Besides studies with minimal risk, waivers of consent may be obtained in a military setting. According to 10 USC 980, the United States Code for the Armed Forces, Limitations on the Use of Humans as Experimental Subjects, a waiver of advanced informed consent may be granted by the Secretary of Defense if a research project would:[6]

text:
Directly benefit subjects.
Advance the development of a medical product necessary to the military.
Be carried out under all laws and regulations (i.e., Emergency Research Consent Waiver) including those pertinent to the FDA.

text: While informed consent is a basic right and should be carried out effectively, if a patient is incapacitated due to injury or illness, it is still important that patients benefit from emergency experimentation.[7] The Food and Drug Administration (FDA) and the Department of Health and Human Services (DHHS) joined together to create federal guidelines to permit emergency research, without informed consent.[7] However, they can only proceed with the research if they obtain a waiver of informed consent (WIC) or an emergency exception from informed consent (EFIC).[7]

text: History[edit]

text: Informed consent is a technical term first used by attorney, Paul G. Gebhard, in a medical malpractice United States court case in 1957.[8] In tracing its history, some scholars have suggested tracing the history of checking for any of these practices:[9]:54

text:
A patient agrees to a health intervention based on an understanding of it.
The patient has multiple choices and is not compelled to choose a particular one.
The consent includes giving permission.

text: These practices are part of what constitutes informed consent, and their history is the history of informed consent.[9]:60 They combine to form the modern concept of informed consent—which rose in response to particular incidents in modern research.[9]:60 Whereas various cultures in various places practiced informed consent, the modern concept of informed consent was developed by people who drew influence from Western tradition.[9]:60

text: Medical history[edit]

text: Historians cite a series of medical guidelines to trace the history of informed consent in medical practice.

text: The Hippocratic Oath, a 500 BC Greek text, was the first set of Western writings giving guidelines for the conduct of medical professionals. It advises that physicians conceal most information from patients to give the patients the best care.[9]:61 The rationale is a beneficence model for care—the doctor knows better than the patient, and therefore should direct the patient's care, because the patient is not likely to have better ideas than the doctor.[9]:61

text: Henri de Mondeville, a French surgeon who in the 14th century, wrote about medical practice. He traced his ideas to the Hippocratic Oath.[9]:63[10][11] Among his recommendations were that doctors "promise a cure to every patient" in hopes that the good prognosis would inspire a good outcome to treatment.[9]:63 Mondeville never mentioned getting consent, but did emphasize the need for the patient to have confidence in the doctor.[9]:63 He also advised that when deciding therapeutically unimportant details the doctor should meet the patients' requests "so far as they do not interfere with treatment".[12]

text: Benjamin Rush was an 18th-century United States physician who was influenced by the Age of Enlightenment cultural movement.[9]:65 Because of this, he advised that doctors ought to share as much information as possible with patients. He recommended that doctors educate the public and respect a patient's informed decision to accept therapy.[9]:65 There is no evidence that he supported seeking a consent from patients.[9]:65 In a lecture titled "On the duties of patients to their physicians", he stated that patients should be strictly obedient to the physician's orders; this was representative of much of his writings.[9]:65 John Gregory, Rush's teacher, wrote similar views that a doctor could best practice beneficence by making decisions for the patients without their consent.[9]:66[13]

text: Thomas Percival was a British physician who published a book called Medical Ethics in 1803.[9]:68 Percival was a student of the works of Gregory and various earlier Hippocratic physicians.[9]:68 Like all previous works, Percival's Medical Ethics makes no mention of soliciting for the consent of patients or respecting their decisions.[9]:68 Percival said that patients have a right to truth, but when the physician could provide better treatment by lying or withholding information, he advised that the physician do as he thought best.[9]:68

text: When the American Medical Association was founded they in 1847 produced a work called the first edition of the American Medical Association Code of Medical Ethics.[9]:69 Many sections of this book are verbatim copies of passages from Percival's Medical Ethics.[9]:69 A new concept in this book was the idea that physicians should fully disclose all patient details truthfully when talking to other physicians, but the text does not also apply this idea to disclosing information to patients.[9]:70 Through this text, Percival's ideas became pervasive guidelines throughout the United States as other texts were derived from them.[9]:70

text: Worthington Hooker was an American physician who in 1849 published Physician and Patient.[9]:70 This medical ethics book was radical demonstrating understanding of the AMA's guidelines and Percival's philosophy and soundly rejecting all directives that a doctor should lie to patients.[9]:70 In Hooker's view, benevolent deception is not fair to the patient, and he lectured widely on this topic.[9]:70 Hooker's ideas were not broadly influential.[9]:70

text: Research history[edit]

text: Historians cite a series of human subject research experiments to trace the history of informed consent in research.

text: The U.S. Army Yellow Fever Commission “is considered the first research group in history to use consent forms.”[14] In 1900, Major Walter Reed was appointed head of the four man U.S. Army Yellow Fever Commission in Cuba that determined mosquitoes were the vector for yellow fever transmission. His earliest experiments were probably done without formal documentation of informed consent. In later experiments he obtained support from appropriate military and administrative authorities. He then drafted what is now “one of the oldest series of extant informed consent documents.”[15] The three surviving examples are in Spanish with English translations; two have an individual’s signature and one is marked with an X.[16]

text: Tearoom Trade is the name of a book by American psychologist Laud Humphreys. In it he describes his research into male homosexual acts.[17] In conducting this research he never sought consent from his research subjects and other researchers raised concerns that he violated the right to privacy for research participants.[17]

text: The Milgram experiment is the name of a 1961 experiment conducted by American psychologist Stanley Milgram. In the experiment Milgram had an authority figure order research participants to commit a disturbing act of harming another person.[18] After the experiment he would reveal that he had deceived the participants and that they had not hurt anyone, but the research participants were upset at the experience of having participated in the research.[18] The experiment raised broad discussion on the ethics of recruiting participants for research without giving them full information about the nature of the research.[18]

text: Chester M. Southam used HeLa cells to inject into cancer patients and Ohio State Penitentiary inmates without informed consent to determine if people could become immune to cancer and if cancer could be transmitted.[19]

text: Medical procedures[edit]

text: The doctrine of informed consent relates to professional negligence and establishes a breach of the duty of care owed to the patient (see duty of care, breach of the duty, and respect for persons). The doctrine of informed consent also has significant implications for medical trials of medications, devices, or procedures.

text: Requirements of the professional[edit]

text: Until 2015 in the United Kingdom and in countries such as Malaysia and Singapore, informed consent in medical procedures requires proof as to the standard of care to expect as a recognised standard of acceptable professional practice (the Bolam Test), that is, what risks would a medical professional usually disclose in the circumstances (see Loss of right in English law). Arguably, this is "sufficient consent" rather than "informed consent." The UK has since departed from the Bolam test for judging standards of informed consent, due to the landmark ruling in Montgomery v Lanarkshire Health Board. This moves away from the concept of a reasonable physician and instead uses the standard of a reasonable patient, and what risks an individual would attach significance to.

text: Medicine in the United States, Australia, and Canada also takes this patient-centric approach to "informed consent." Informed consent in these jurisdictions requires healthcare providers to disclose significant risks, as well as risks of particular importance to that patient. This approach combines an objective (a hypothetical reasonable patient) and subjective (this particular patient) approach.

text: The doctrine of informed consent should be contrasted with the general doctrine of medical consent, which applies to assault or battery. The consent standard here is only that the person understands, in general terms, the nature of and purpose of the intended intervention. As the higher standard of informed consent applies to negligence, not battery, the other elements of negligence must be made out. Significantly, causation must be shown: That had the individual been made aware of the risk he would not have proceeded with the operation (or perhaps with that surgeon).

text: Optimal establishment of an informed consent requires adaptation to cultural or other individual factors of the patient. For example, people from Mediterranean and Arab appear to rely more on the context of the delivery of the information, with the information being carried more by who is saying it and where, when, and how it's being said, rather than what is said, which is of relatively more importance in typical "Western" countries.[20]

text: The informed consent doctrine is generally implemented through good healthcare practice: pre-operation discussions with patients and the use of medical consent forms in hospitals. However, reliance on a signed form should not undermine the basis of the doctrine in giving the patient an opportunity to weigh and respond to the risk. In one British case, a doctor performing routine surgery on a woman noticed that she had cancerous tissue in her womb. He took the initiative to remove the woman's womb; however, as she had not given informed consent for this operation, the doctor was judged by the General Medical Council to have acted negligently. The council stated that the woman should have been informed of her condition, and allowed to make her own decision.

text: Obtaining informed consents[edit]

text: To capture and manage informed consents, hospital management systems typically use paper-based consent forms which are scanned and stored in a document handling system after obtaining the necessary signatures. Hospital systems and research organizations are adopting an electronic way of capturing informed consents to enable indexing, to improve comprehension, search and retrieval of consent data, thus enhancing the ability to honor to patient intent and identify willing research participants.[21][22][23][24] More recently, Health Sciences South Carolina, a statewide research collaborative focused on transforming healthcare quality, health information systems and patient outcomes, developed an open-source system called Research Permissions Management System (RPMS).[25][26]

text: Competency of the patient[edit]

text: The ability to give informed consent is governed by a general requirement of competency. In common law jurisdictions, adults are presumed competent to consent. This presumption can be rebutted, for instance, in circumstances of mental illness or other incompetence. This may be prescribed in legislation or based on a common-law standard of inability to understand the nature of the procedure. In cases of incompetent adults, a health care proxy makes medical decisions. In the absence of a proxy, the medical practitioner is expected to act in the patient's best interests until a proxy can be found.

text: By contrast, 'minors' (which may be defined differently in different jurisdictions) are generally presumed incompetent to consent, but depending on their age and other factors may be required to provide Informed assent. In some jurisdictions (e.g. much of the U.S.), this is a strict standard. In other jurisdictions (e.g. England, Australia, Canada), this presumption may be rebutted through proof that the minor is ‘mature’ (the ‘Gillick standard’). In cases of incompetent minors, informed consent is usually required from the parent (rather than the 'best interests standard') although a parens patriae order may apply, allowing the court to dispense with parental consent in cases of refusal.

text: Deception[edit]

text: Research involving deception is controversial given the requirement for informed consent. Deception typically arises in social psychology, when researching a particular psychological process requires that investigators deceive subjects. For example, in the Milgram experiment, researchers wanted to determine the willingness of participants to obey authority figures despite their personal conscientious objections. They had authority figures demand that participants deliver what they thought was an electric shock to another research participant. For the study to succeed, it was necessary to deceive the participants so they believed that the subject was a peer and that their electric shocks caused the peer actual pain.

text: Nonetheless, research involving deception prevents the subject/patient from exercising his/her basic right of autonomous informed decision-making and conflicts with the ethical principle of respect for persons.

text: The Ethical Principles of Psychologists and Code of Conduct set by the American Psychological Association says that psychologists may not conduct research that includes a deceptive compartment unless they can justify the act by the value and importance of the study's results, and show they couldn't obtain the results by some other way. Moreover, the research should bear no potential harm to the subject as an outcome of deception, be it physical pain or emotional distress. Finally, the code requires a debriefing session, in which the experimenter tells the subject about the deception, and gives subjects the option of withdrawing their data.[27]

text: Abortion[edit]

text: In some U.S. states, informed consent laws (sometimes called "right to know" laws) require that a woman seeking an elective abortion receive information from the abortion provider about her legal rights, alternatives to abortion (such as adoption), available public and private assistance, and other information specified in the law, before the abortion is performed. Other countries with such laws (e.g. Germany) require that the information giver be properly certified to make sure that no abortion is carried out for the financial gain of the abortion provider and to ensure that the decision to have an abortion is not swayed by any form of incentive.[28][29]

text: Some informed consent laws have been criticized for allegedly using "loaded language in an apparently deliberate attempt to 'personify' the fetus,"[30] but those critics acknowledge that "most of the information in the [legally mandated] materials about abortion comports with recent scientific findings and the principles of informed consent", although "some content is either misleading or altogether incorrect."[31]

text: Children[edit]

text: As children often lack the decision making ability or legal power (competence) to provide true informed consent for medical decisions, it often falls on parents or legal guardians to provide informed permission for medical decisions. This "consent by proxy" usually works reasonably well, but can lead to ethical dilemmas when the judgment of the parents or guardians and the medical professional differ with regard to what constitutes appropriate decisions "in the best interest of the child". Children who are legally emancipated, and certain situations such as decisions regarding sexually transmitted diseases or pregnancy, or for unemancipated minors who are deemed to have medical decision making capacity, may be able to provide consent without the need for parental permission depending on the laws of the jurisdiction the child lives in. The American Academy of Pediatrics encourages medical professionals also to seek the assent of older children and adolescents by providing age appropriate information to these children to help empower them in the decision making process.[32]

text: Research on children has benefited society in many ways. The only effective way to establish normal patterns of growth and metabolism is to do research on infants and young children. When addressing the issue of informed consent with children, the primary response is parental consent. This is valid, although only legal guardians are able to consent for a child, not adult siblings.[33] Additionally, parents may not order the termination of a treatment that is required to keep a child alive, even if they feel it is in the best interest.[33] Guardians are typically involved in the consent of children, however a number of doctrines have developed that allow children to receive health treatments without parental consent. For example, emancipated minors may consent to medical treatment, and minors can also consent in an emergency.[33]

text: Research[edit]

text: Informed consent is part of the ethical clinical research as well, in which a human subject voluntarily confirms his or her willingness to participate in a particular clinical trial, after having been informed of all aspects of the trial that are relevant to the subject's decision to participate. Informed consent is documented by means of a written, signed, and dated informed consent form.[34] In medical research, the Nuremberg Code set a base international standard in 1947, which continued to develop, for example in response to the ethical violation in the Holocaust. Nowadays, medical research is overseen by an ethics committee that also oversees the informed consent process.

text: As the medical guidelines established in the Nuremberg Code were imported into the ethical guidelines for the social sciences, informed consent became a common part of the research procedure.[35] However, while informed consent is the default in medical settings, it is not always required in the social science. Here, research often involves low or no risk for participants, unlike in many medical experiments. Second, the mere knowledge that they participate in a study can cause people to alter their behavior, as in the Hawthorne Effect: "In the typical lab experiment, subjects enter an environment in which they are keenly aware that their behavior is being monitored, recorded, and subsequently scrutinized."[36]:168 In such cases, seeking informed consent directly interferes with the ability to conduct the research, because the very act of revealing that a study is being conducted is likely to alter the behavior studied. List exemplifies the potential dilemma that can result: "if one were interested in exploring whether, and to what extent, race or gender influences the prices that buyers pay for used cars, it would be difficult to measure accurately the degree of discrimination among used car dealers who know that they are taking part in an experiment."[37] In cases where such interference is likely, and after careful consideration, a researcher may forgo the informed consent process. This is commonly done after weighting the risk to study participants versus the benefit to society and whether participants are present in the study out of their own wish and treated fairly.[38] Researchers often consult with an ethics committee or institutional review board to render a decision.

text: The birth of new online media, such as social media, has complicated the idea of informed consent. In an online environment people pay little attention to Terms of Use agreements and can subject themselves to research without thorough knowledge. This issue came to the public light following a study conducted by Facebook Inc. in 2014, and published by that company and Cornell University.[39] Facebook conducted a study where they altered the Facebook News Feeds of roughly 700,000 users to reduce either the amount of positive or negative posts they saw for a week. The study then analyzed if the users status updates changed during the different conditions. The study was published in the Proceedings of the National Academy of Sciences.

text: The lack of informed consent led to outrage among many researchers and users.[40] Many believed that by potentially altering the mood of users by altering what posts they see, Facebook put at-risk individuals at higher dangers for depression and suicide. However, supports of Facebook claim that Facebook details that they have the right to use information for research in their terms of use.[41] Others say the experiment is just a part of Facebook’s current work, which alters News Feeds algorithms continually to keep people interested and coming back to the site. Others pointed out that this specific study is not along but that news organizations constantly try out different headlines using algorithms to elicit emotions and garner clicks or Facebook shares.[42] They say this Facebook study is no different than things people already accept. Still, others say that Facebook broke the law when conducting the experiment on user that didn’t give informed consent.[43]

text: The Facebook study controversy raises numerous questions about informed consent and the differences in the ethical review process between publicly and privately funded research. Some say Facebook was within its limits and others see the need for more informed consent and/or the establishment of in-house private review boards.[44]

text: Conflicts of interest[edit]

text: Other, long-standing controversies underscore the role for conflicts of interest among medical school faculty and researchers. For example, coverage of University of California (UC) medical school faculty members has included news of ongoing corporate payments to researchers and practitioners from companies that market and produce the very devices and treatments they recommend to patients.[45] Robert Pedowitz, the former chairman of UCLA’s orthopedic surgery department, reported concern that his colleague’s financial conflicts of interest could negatively affect patient care or research into new treatments.[46] In a subsequent lawsuit about whistleblower retaliation, the University provided a $10 million settlement to Pedowitz while acknowledging no wrongdoing.[46] Consumer Watchdog, an oversight group, observed that University of CA policies were “either inadequate or unenforced…Patients in UC hospitals deserve the most reliable surgical devices and medication…and they shouldn’t be treated as subjects in expensive experiments.”[45] Other UC incidents include taking the eggs of women for implantation into other women without consent[47] and injecting live bacteria into human brains, resulting in potentially premature deaths.[48]


document_title: Internet studies

question_text: when did communication scholars start to research new technologies like the internet

text: Internet studies

text: Topics of study[edit]

text: In recent years, Internet studies have become institutionalized as courses of study at several institutions of higher learning, including the University of Oxford, Harvard University, London School of Economics, Curtin University of Technology, Brandeis University, Endicott College, Hebrew University of Jerusalem, Appalachian State University and the University of Minnesota.

text: Disciplines that contribute to Internet studies include:

text:
Computer-mediated communication: such as the role of e-mail, social media, MMORPGs, online chat, blogs, and text messaging in communication processes.
Digital rights: including privacy, free speech, intellectual property, and digital rights management.
Digital Labour and the "Gig Economy"
Internet architecture: including the fundamental programming and architecture of the Internet, such as TCP/IP, HTML, CSS, CGI, CFML, DOM, JS, PHP, XML.
Internet culture: including the emergence of Internet slang, Cyberculture and digital music.
Internet security: such as the structure and propagation of viruses, malware, and software exploits, as well as methods of protection, including antivirus programs and firewalls.
Online communities: including Internet forums, blogs, and MMORPGs.
Open source software: focusing on the ability of Internet users to collaborate to modify, develop, and improve pieces of software which are freely available to the public without charge.
Sociology of the Internet: including the social implications of the Internet, new social networks, online societies (virtual communities), identity practices and social interaction on the Internet.
Science and Technology Studies: how and why we have the digital technologies we have, and how social shapes their development.

text: Key authors[edit]

text: A number of academic journals are central to communicating research in the field, including Bad Subjects, Convergence: The Journal of Research into New media Technologies, Ctheory, Cyber Psychology + Behaviour, Computers in Human Behavior,[3] First Monday, Information, Communication, and Society, The Information Society, Journal of Computer-Mediated Communication, M/C, New Media & Society, tripleC: Journal for a Global Sustainable Information Society,  Fibreculture Journal,[4] and TeknoKultura,[5] but research relating to internet studies appears in a diverse range of venues and disciplines.

text: Key foundational work, that developed in to Internet Studies, is found in studies of the Information Society and the Network Society by scholars such as Manuel Castells, Mark Poster, Frank Webster, etc. Other important authors are Sherry Turkle and Robert Kraut for their socio-psychological contributions; Abbate and Patrice Flichy for their socio-historical research; Barry Wellman and Caroline Haythornwaite for their social network approaches; Ronald E. Rice for his information science contributions; David Lyon and Philip Agre for their privacy and surveillance writings; Lawrence Lessig, Andrew Chadwick, Jonathan Zittrain for their study of law and politics; and Robin Williams, Robin Mansell and Steve Woolgar for their contributions about innovation.

text: History[edit]

text: As Barry Wellman argues, internet studies may find its beginnings with the 1978 publication of The Network Nation,[6] and was largely dominated by computer scientists, presenting at venues like the annual CSCW conference. These were quickly joined by researchers in business fields and library and information science.[7] By the late 1990s, more attention was being paid to systematic investigation of users and how they made use of the new technologies. During the 1990s, the rapid diffusion of internet access began to attract more attention from a number of social science and humanities disciplines, including the field of communication.[8] Some of these investigations, like the Pew Internet & American Life project[9] and the World Internet Project[10] framed the research in terms of traditional social science approaches, with a focus less on the technology than on those who use them. But the focus remained at the aggregate level. In the UK, the ESRC Programme on Information and Communications Technologies (1986–1996)[11] laid considerable ground work on how society and ICTs interact, bringing together important clusters of scholars from media and communications, society, innovation, law, policy and industry across leading UK universities.

text: In 1996, this interest was expressed in other ways as well. Georgetown University began offering a related master's program in that year, and at the University of Maryland, David Silver created the Resource Center for Cyberculture Studies[12] on the web. Middlebury College developed Politics of Virtual Realities, one of the first undergraduate courses dedicated to exploring the political, legal and normative implications of the Internet for liberal democracy.[13] By 2001, The Chronicle of Higher Education noted that "internet studies" was emerging as a discipline in its own right, as suggested by the first undergraduate program in the area, offered at Brandeis University, and noted that "perhaps the most telling sign of the field's momentum" was the popularity of the annual conference created by the then nascent Association of Internet Researchers.[14]

text: From particularly sociological perspective,  James Slevin (2000)[15] develops a social theory of the Internet that is primarily informed by the line of thought grounded by the British sociologist Anthony Giddens., while Christian Fuchs (2008)[16] is a social theory account that is primarily grounded in the works by critical theory scholars such as Herbert Marcuse, by the concept of social self-organization, and by neo-Marxist thinking.[citation needed][original research?]

text: More recent approaches to studying the internet have focused on situating technology use within particular social contexts, and understanding just how it is related to social and institutional change.

text: Scholarly organizations[edit]

text:
American Society for Information Science and Technology (ASIST)
American Sociological Association, Section on Communication and Information Technologies (CITASA)
Association of Internet Researchers (AoIR)
Association for Education in Journalism and Mass Communication, Communication & Technology Division (CTEC)
Association for Computing Machinery (ACM)
European Association for the Study of Science and Technology
European Consortium for Political Research (ECPR) Internet & Politics Standing Group (SG)
International Communication Association Communication & Technology (CAT) division
International Association for Media and Communication Research
National Communication Association (NCA) Human Communication and Technology Division (HCTD)
Society for Social Studies of Science

text: Cognate fields[edit]

text:
Electronic commerce
Human–computer interaction
Internet research ethics
Library science
Science and technology studies
Web science