The 1570 5.25-inch floppy disk (also Commodore-1570 or CBM-1570) was Commodore's first C128 disk drive. Production started in 1985. The hardware is a cross between the 1541 and the 1571, and like the VIC-1540/1541/1551, the 1570 has one head for reading/writing. However, it reads/writes two disk formats: first, the usual GCR format from Commodore, and second, the MFM format used by PCs (for CP/M software). The 1570 unit connects via the serial bus to the C64/C128/D/DCR, plus C16/116 and Plus/4 resp. VIC-20. As with the 1541, the disk unit also houses an integrated mains adapter. A front latch secures inserted floppy disks. The device number (8-11) can be changed via DIP-switches, but this requires removal of the cover. The 1570 operates via Commodore DOS 3.0 or 3.1. Data transfer in ‘burst-mode’ is about 10 times (3,000 bytes per second) faster than the older 1541 drive.
GCR format[edit | edit source]
Recording in the GCR format (Group Coded Recording).
On each Disk there are 174,848 bytes available, from which 664 blocks are usable and the maximum amount of entries in the directory is limited to 144.
The disk drive 1570 recognizes the following file formats:
- PRG program files (max. file size 200 blocks)
- SEQ sequential files (for data storage of applications; max. file size 168.656 bytes)
- USR user files (special form of sequential data)
- REL relative files (also for data storage of applications; max. file size 167.132 Bytes with max. 65.535 records)
- DEL deleted file (can be made visible with tricks resp. manipulation of the directory)
- If the character < is displayed behind the file name, the file has a write protection by software.
- If a * is displayed, the file seems not to be closed properly. This can be fixed by using the VALIDATE command, NOT the SCRATCH command.
MFM format[edit | edit source]
Recording in the MFM format (Modified Frequency Modulation).
An unformatted disk will be recognized with 500.000 Bytes, although depending on the used sector size (128/256/512/1024 Bytes) only 130/160/180 or 200 kByte can be used. The maximum number of tracks is 40 from which depending on the sector size (128/256/512/1024) 26, 16, 9 or 5 sectors will be used.
Technical Data[edit | edit source]
- Chips used: 6502A (CPU) running at 1-2MHz, 6522, 6526
- ROM with 32KByte: 23256
- RAM with 2 KByte: 6116
- Gate Array: 64H156/64H157
- Analog switch: R/W hybrid circuit
- Disk-Controller: WD 1770
- Dimensions: 97*200*374 mm
- Weigth: 3,5 kg
- Power supply: 100,120,220 or 240V with 50 or 60 Hz
- Power input: 25W
Memory mapping and Test-/Demodisk of the 1570[edit | edit source]
The memory mapping and the content of the Test-/Demodisk of the 1570 is same than for the disk drive 1571.
Controlling the disk drive[edit | edit source]
The disk drive 1570 can be controlled through the following methods:
- Basic commands in the command mode
- Basic commands in programs or programs
- Special disk commands
Links[edit | edit source]