DiscTester

WacKEDmaN · September 30, 2026, 6:11am

got claude to write a nice disk tester/viewer, that shows various info about each block on the disk..

shows a nice circular view aswell

ive got some bad disks and wanted to actually see where they are bad on the disk

docs/DiscTester.md

main

# DISCTEST – floppy disc tester for the Amstrad CPC

`disctest.asm` checks a floppy disc and draws a colour map of every track and
sector. The map shows which sectors are bad, which hold data, and what kind of
data each one holds. It programs the uPD765 floppy disc controller directly,
so it can read any format the CPC hardware can read, on 3" and 3.5" drives. It
**only reads**; it never writes to the disc.

Works on a CPC 664, a CPC 6128 or a CPC 464 with a DDI-1 disc interface, using
drive A or B.

![map of the error test disc](screenshots/map_errors.png)

## Building

```
./build.sh          # needs pasmo and python3
```

This produces `build/disctest.bin`, the raw code (load and run address &0800),

This file has been truncated. show original

disctest.dsk (190.3 KB)

github.com/WacKEDmaN/Z80ASM

disctest.asm

main

;; ==========================================================================
;; DISCTEST.ASM - Floppy disc surface tester for the Amstrad CPC
;; ==========================================================================
;;
;; Talks directly to the uPD765 floppy disc controller (CPC 664/6128, or a
;; 464 with DDI-1) and scans every track and side of a disc.  Every sector
;; found is read and shown as a coloured cell on a map of the disc:
;;
;;      columns = tracks, rows = sectors (sorted by sector ID)
;;
;; For every sector the program records the ID (C,H,R,N), the FDC status
;; (ST1/ST2), how many retries it needed and what kind of data it holds
;; (empty, filler, directory, AMSDOS file header, text, binary, CP/M system
;; track) or what kind of error it has (data CRC, ID CRC / sector not found /
;; no data mark, deleted data mark, weak sector, unformatted track).
;;
;; Nothing is ever written to the disc - the program only issues SPECIFY,
;; RECALIBRATE, SEEK, SENSE INTERRUPT STATUS, SENSE DRIVE STATUS, READ ID and
;; READ DATA commands.
;;

This file has been truncated. show original

Gryzor · September 30, 2026, 6:23am

Heh, that’s nice. Can you share your workflow with Claude?

WacKEDmaN · September 30, 2026, 6:29am

single shot prompt to get the main map…i was using claude cloud linked to github..

“i want you to write me a z80 assembly program for amstrad cpc that tests floppy discs, graphically shows all tracks and sectors, and show which ones are bad, which have data, the type of data, etc etc… it should support all the floppy disk formats the cpc can support (3 and 3.5in)”

2nd prompt “is it possible to make a graphical disc with the sectors and tracks laid out… like a circular disk…maybe use mode 1 or 2 for more resolution”

it created a new branch on my github, added the images, readme, and asm, and even built a dsk image!

Gryzor · September 30, 2026, 6:32am

Thanks, interesting. And it created the dsk by itself, no prompting???

WacKEDmaN · September 30, 2026, 6:37am

no prompting to build the dsk image…

it even built caprice to use for testing and screenshots!

Gryzor · September 30, 2026, 6:38am

Ha that’s great

cpcitor · October 1, 2026, 8:41pm

Only half-joking: the model has learn from cpc-dev-tool-chain, CPCTelera and other tools.

slider271 · October 1, 2026, 8:43pm

well that’s how AI works, scraping other people’s sites and content, taking away clicks and views

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DiscTester

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