group code recording การใช้

• IBM documents refer to the error correcting code itself as " group coded recording ".
• The Group Code Recording ( GCR ) scheme of binary encoding is used to store data on the magnetic disk medium.
• The " Optimal Rectangular Code " used in group code recording tapes not only detects but also corrects single-bit errors.
• It was quickly replaced by double density floppy drives using modified frequency modulation ( MFM ) or group code recording ( GCR ).
• The disk drive uses group code recording ( GCR ) and contains a MOS Technology 6502 microprocessor, doubling as a disk controller and on-board disk operating system processor.
• However, Apple's custom interface used GCR ( Group Code Recording ) and a unique format which put fewer sectors on the smaller inner tracks and more sectors on the wider outer tracks of the disk.
• All of the models in the 8060 series use Commodore group code recording ( GCR ) for disk reading and writing; the later 8061 and 8062 models can also read and write CBM DOS 2.7.
• The Group Code Recording used by the controller was simpler and easier to implement in software than the more common copy-protect the media on which their software shipped by changing the low-level sector format or stepping the drive's head between the tracks; inevitably, other companies eventually sold software to foil this protection.