Editing The Anatomy of the 1541 Disk Drive

'''''The Anatomy of the 1541 Disk Drive: A Complete Guide to Using The Commodore Disk Drive''''' by '''Lothar Englisch and Norbert Szczepanowski''', edited by Greg Dykema and Arnie Lee. '''A Data Becker book''', published in the UK by '''First Publishing Ltd''', Pangbourne, Berkshire, '''ISBN 0-948015-012'''; copyright Data Becker GmbH and Abacus Software 1983/1984, First Publishing 1984. '''340 pages'''. The scan is from the '''retro-commodore.eu''' archive (Tomse), processed with ABBYY, and carries a searchable text layer.

== What it contains ==
Five chapters:

* '''Chapter 1 — Programming the VIC-1541''' (pp. 1–81): the DOS, the TEST/DEMO diskette, formatting, SAVE/LOAD/VERIFY, machine-language program storage, disk system commands, sequential and relative files, '''disk error messages and their causes (p. 72)''', and a comparison of BASIC 2.0, BASIC 4.0 and DOS 5.1 commands (p. 77).
* '''Chapter 2 — Advanced Programming''' (from p. 82): direct block access and all six direct-access commands (BLOCK-READ, BLOCK-POINTER, BLOCK-WRITE, BLOCK-ALLOCATE, BLOCK-FREE, BLOCK-EXECUTE), and accessing the DOS.
* '''Chapter 3''' — the '''documented DOS listing'''. This is the heart of the book: a commented disassembly of the 1541's Disk Operating System. '''165 of the 340 pages contain 6502 assembly listings.'''
* '''Chapter 4''' (to p. 316): reading the directory from a program, the TEST/DEMO utilities (DOS 5.1, COPY/ALL, DISK ADDR CHANGE, DIR, VIEW BAM, CHECK DISK, DISPLAY T&S, PERFORMANCE TEST), BASIC extensions, overlay and chaining techniques, MERGE, and a disk monitor for the C64 and VIC-20.
* '''Chapter 5 — The Larger CBM Disks''' (pp. 317–319): the IEEE and serial buses, and a comparison of all CBM disk drives.

== What it does not contain — read this before citing it ==
'''There is no schematic in this book, and no parts list, no component values, no alignment procedure, no head-adjustment procedure and no voltage figures.''' Searching the full 340-page text layer for "schematic", "circuit diagram", "block diagram", "parts list", "alignment" and "voltage" returns nothing.

That matters because the title invites the opposite assumption, and because the same assumption has already been shown to be wrong for the companion volume ''The Anatomy of the Commodore 64''. '''The Anatomy of the 1541 is a software book about the drive's firmware, not a hardware book about the drive.'''

It does document the drive's controller at the register level — the 6502 and both 6522 VIAs appear in the DOS listing — which is useful if you are chasing a firmware or protocol fault, and useless if you are chasing a dead motor.

== What to use instead for hardware ==
* '''[[Commodore 1541 Troubleshooting & Repair Guide]]''' — the Sams book, which '''does''' carry theory of operation, schematics, parts layouts and parts lists, with the drive motor servo circuit documented separately for the 1540, 1541 and 1542. That is the hardware source on this wiki.
* [[Floppy Drive Repair]] for general cleaning, lubrication and alignment.

== Related pages ==
* [[Commodore 1541 Troubleshooting & Repair Guide]] · [[Floppy Drive Repair]]
* [[Commodore 64]] · [[:Category:Commodore Books]]
* [[Machine Language for Beginners]] — 6502 machine language across the Commodore, Atari and Apple machines; note that about 117 printed pages are missing from that scan
* [[Very Basic BASIC]] · [[The Micro Enquirer]] · [[Run Works]] · [[Leaning through LOGO]] — the rest of the Commodore software shelf

<pdf> File:The_Anatomy_of_the_1541_Disk_Drive.pdf </pdf>

Download '''The Anatomy of the 1541 Disk Drive''' here: [[:File:The_Anatomy_of_the_1541_Disk_Drive.pdf|The_Anatomy_of_the_1541_Disk_Drive.pdf]] (17 MB)

[[Category:Commodore Documentation]]
[[Category:Commodore Books]]