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63 lines
2.7 KiB
Markdown
63 lines
2.7 KiB
Markdown
victor9k
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====
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## 1224kB 5.25" DSDD GCR
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<!-- This file is automatically generated. Do not edit. -->
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The Victor 9000 / Sirius One was a rather strange old 8086-based machine
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which used a disk format very reminiscent of the Commodore format; not a
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coincidence, as Chuck Peddle designed them both. They're 80-track, 512-byte
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sector GCR disks, with a variable-speed drive and a varying number of sectors
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per track --- from 19 to 12. Disks can be double-sided, meaning that they can
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store 1224kB per disk, which was almost unheard of back then. Because the way
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that the tracks on head 1 are offset from head 0 (this happens with all disks),
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the speed zone allocation on head 1 differs from head 0...
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| Zone | Head 0 tracks | Head 1 tracks | Sectors | Original period (ms) |
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|:----:|:-------------:|:-------------:|:-------:|:--------------------:|
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| 0 | 0-3 | | 19 | 237.9 |
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| 1 | 4-15 | 0-7 | 18 | 224.5 |
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| 2 | 16-26 | 8-18 | 17 | 212.2 |
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| 3 | 27-37 | 19-29 | 16 | 199.9 |
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| 4 | 38-47\* | 30-39\* | 15 | 187.6 |
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| 5 | 48-59 | 40-51 | 14 | 175.3 |
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| 6 | 60-70 | 52-62 | 13 | 163.0 |
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| 7 | 71-79 | 63-74 | 12 | 149.6 |
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| 8 | | 75-79 | 11 | 144.0 |
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(The Original Period column is the original rotation rate. When used in
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FluxEngine, the disk always spins at 360 rpm, which corresponds to a rotational
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period of 166 ms.)
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\*The Victor 9000 Hardware Reference Manual has a bug in the documentation
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and lists Zone 4 as ending with track 48 on head 0 and track 40 on head 1.
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The above table matches observed data on various disks and the assembly
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code in the boot loader, which ends Zone 4 with track 47 on head 0
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and track 39 on Head 1.
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FluxEngine can read and write both the single-sided and double-sided variants.
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## Options
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- Format variants:
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- `612`: 612kB 80-track DSHD GCR
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- `1224`: 1224kB 80-track DSHD GCR
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## Examples
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To read:
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- `fluxengine read -c victor9k --612 -s drive:0 -o victor9k.img`
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- `fluxengine read -c victor9k --1224 -s drive:0 -o victor9k.img`
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To write:
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- `fluxengine write -c victor9k --612 -d drive:0 -i victor9k.img`
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- `fluxengine write -c victor9k --1224 -d drive:0 -i victor9k.img`
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## References
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- [The Victor 9000 technical reference manual](http://bitsavers.org/pdf/victor/victor9000/Victor9000TechRef_Jun82.pdf)
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- [DiskFerret's Victor 9000 format guide](https://discferret.com/wiki/Victor_9000_format)
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