Encoding methods for representing data on magnetic media
In computer science, group coded recording or group code recording (GCR) refers to several distinct but related encoding methods for representing data on magnetic media. The first, used in 6250 bpi magnetic tape since 1973, is an error-correcting code combined with a run-length limited (RLL) encoding scheme, belonging into the group of modulation codes.[1] The others are different mainframe hard disk as well as floppy disk encoding methods used in some microcomputers until the late 1980s. GCR is a modified form of a NRZI code, but necessarily with a higher transition density.[1]
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introduction of 6250 bpi tapes which used the more efficient group-codedrecording. Manchester code was used in early Ethernet physical layer standards and is...
generators of G{\displaystyle G}. Groupcodedrecording (GCR) Watkinson, John (1990). "3.4. Groupcodes". Coding for Digital Recording. Stoneham, MA, USA: Focal...
extra header byte is what causes this write incompatibility. The GroupCodedRecording (GCR) scheme of binary encoding is used to store data on the magnetic...
the Commodore 1540 (meant for the VIC-20). The disk drive uses groupcodedrecording (GCR) and contains a MOS Technology 6502 microprocessor, doubling...
magnetic tape data storage in 1951. The optimal rectangular code used in groupcodedrecording tapes not only detects but also corrects single-bit errors...
gray ink in color printing Groupcodedrecording, a technique for encoding digital data on magnetic tape or disk GCR, ICAO code for Tianjin Airlines, China...
tracks per side. Data is encoded using Commodore's proprietary groupcodedrecording scheme. Soft sectoring is used for track alignment. Like most other...
Shugart SA-800s. All of the models in the 8060 series use Commodore groupcodedrecording (GCR) for disk reading and writing; the later 8061 and 8062 models...
stamped with the Apple logo. Steve Wozniak developed a recording scheme known as GroupCodedRecording which allowed 140k of storage, well above the standard...
Retrieved 2012-01-31. "Hard-disk-drive technology flat heads for linear tape recording". Archived from the original on February 16, 2008. Retrieved 2012-01-31...
Manchester encoding (DM), modified frequency modulation (MFM), M2FM and groupcodedrecording (GCR). The 5¼-inch format displaced the 8-inch one for most uses...
portal Apple IIGS (limited edition case molded with Woz's signature) Groupcodedrecording (encoding methods for representing data) Hackers: Heroes of the...
previous Commodore drives. Earlier Commodore drives used a custom groupcodedrecording format that stored 170 kB per side of a disk. This made it fairly...
was used for a group of bits greater than 4. In the Apple II microcomputer line, much of the disk drive control and group-codedrecording was implemented...
computer revolution. After Peddle's death, Mensch wrote in memoriam. Groupcodedrecording Metz, Cade (December 24, 2019). "Chuck Peddle Dies at 82; His $25...
4-to-5-bit codes have been used for magnetic recording and are known as groupcodedrecording (GCR), but those are (0,2) run-length limited codes, with at...
drives used with the later two machines. The standard Commodore GroupCodedRecording (GCR) scheme used in 1541 and compatibles employed four different...
system makes each block its own cluster.: 86 The disk drive uses groupcodedrecording and contains an MOS Technology 6510T processor as a disk controller...
improved line code, such as modified frequency modulation (MFM), modified modified frequency modulation (M²FM), FM/MFM or groupcodedrecording (GCR). SD...
2MB diskettes for use in a FileWare drive. The disk format uses groupcodedrecording (GCR) in a manner very similar to that of the Disk II. The drive...
rotational speed, was approximately constant. This, combined with group-codedrecording (GCR), allowed standard floppy disks to hold more data than others...
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