Linked by Thom Holwerda on Sun 17th Jul 2011 12:01 UTC
Hardware, Embedded Systems "Back in the 80s, the Commodore C-64 had an intelligent floppy drive, the 1541, i.e. an external unit that had its own CPU and everything. The C-64 would send commands to the drive which in turn would then execute them on its own, reading files, and such, then send the data to the C-64, all over a propriatory serial cable. The manual for the 1541 mentioned, besides the commands for reading and writing files, that one would read and write to its internal memory space. Even more exciting was that one could download 6502 code into the drive's memory and have it executed there. This got me hooked and I wanted to play with that - execute code on the drive. Of course, there was no documention on what code could be executed there, and which functions it could use." Very interesting. I'm most interested in how he describes others taking his work, and making it better. This would be impossible today, thanks to Microsoft, Apple, and other patent trolls.
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RE: Slow?
by Dave_K on Mon 18th Jul 2011 14:01 UTC in reply to "Slow?"
Dave_K
Member since:
2005-11-16

I remember running GEOS from a 1541 and being convinced that the drive was faulty. As someone used to the BBC Micro's (relatively) lightning fast drives loading software in a few seconds, I couldn't believe that floppies could be so slow.

At the time the painfully slow drives seemed like the C64's biggest disadvantage as a business computer. It made disk swapping and loading to change between singletasking applications a more frustrating experience, and I can't imagine disks in the 1541 being usable for virtual memory (as they were in some Beeb software).

Reply Parent Score: 3

RE[2]: Slow?
by Zbigniew on Mon 18th Jul 2011 18:11 in reply to "RE: Slow?"
Zbigniew Member since:
2008-08-28

I can't imagine disks in the 1541 being usable for virtual memory (as they were in some Beeb software).

Why not? It depends only on that software - will it use diskette as virtual memory, or not.

Reply Parent Score: 1

RE[3]: Slow?
by Dave_K on Tue 19th Jul 2011 15:13 in reply to "RE[2]: Slow?"
Dave_K Member since:
2005-11-16

Why not? It depends only on that software - will it use diskette as virtual memory, or not.


By "usable" I didn't mean technically possible, I meant practical in real world use.

I remember a BBC DTP app where only the part of the document on screen was stored in memory, and the rest moved to and from virtual memory in real time as it was scrolled through. I doubt that something as fast, efficient and usable as that was could have been achieved with the painfully slow 1541.

Edited 2011-07-19 15:14 UTC

Reply Parent Score: 2