doc:cbm:disk:image:g64
Differences
This shows you the differences between two versions of the page.
Both sides previous revisionPrevious revision | Last revisionBoth sides next revision | ||
doc:cbm:disk:image:g64 [2020/06/01 01:46] – eek | doc:cbm:disk:image:g64 [2020/06/01 01:47] – eek | ||
---|---|---|---|
Line 246: | Line 246: | ||
There is some controversy over the header gap (#3). Most people assume it | There is some controversy over the header gap (#3). Most people assume it | ||
- | to be 9 bytes of 0x55 characters, but the early 1540/1541 drives used only | + | to be 9 bytes of '' |
8. This caused an write incompatability with the existing 4040 disks of the | 8. This caused an write incompatability with the existing 4040 disks of the | ||
day. In 1541 ROM revision 901225-3 this error was fixed, and now all drives | day. In 1541 ROM revision 901225-3 this error was fixed, and now all drives | ||
- | write out 9 of the 0x55 characters for the gap. The book " | + | write out 9 of the '' |
DOS" | DOS" | ||
corruption happens at a low level when writing to a disk with a header | corruption happens at a low level when writing to a disk with a header | ||
Line 282: | Line 282: | ||
- Search for SYNC (at least 10 or more 1 bits) | - Search for SYNC (at least 10 or more 1 bits) | ||
- | - Check for header id after SYNC (GCR 0x52) | + | - Check for header id after SYNC (GCR '' |
- If header, read the remaining 9 header bytes | - If header, read the remaining 9 header bytes | ||
- Decode header and get sector value | - Decode header and get sector value | ||
- Search for SYNC again | - Search for SYNC again | ||
- | - Check for data id after SYNC (GCR 0x55). | + | - Check for data id after SYNC (GCR '' |
- If data, read and store with previous header. | - If data, read and store with previous header. | ||
- Have we finished reading the track... stop | - Have we finished reading the track... stop | ||
- Start over | - Start over | ||
doc/cbm/disk/image/g64.txt · Last modified: 2020/06/01 01:47 by eek