Wow; $192 for a 5.25" floppy disk drive

[Philip Pemberton]

Jules Richardson wrote:
> Maybe someone can think of a situation where you *need* more than one 
> track in memory at once, though. (Note I'm not thinking at all about 
> storage formats which aren't track-based though)

Disc-to-disc imaging?

> DRAM, no. In that sort of situation providing a SIMM / DIMM socket would 
> seem the best bet and people can populate it with whatever memory they 
> have to hand. There is the refresh issue then, though.

Use a CPLD and one of the many free SDRAM-to-SRAM-interface Verilog/VDL models 
- <http://www.cmosexod.com/sdram.html> for example.

> Possibly, depending on cost. I'd hope that something could typically be 
> lashed together (parts cost only) for about 20 bucks, though using a 
> combination of purchased bits and things from the parts bin [1]. Beyond 
> that and it's sort of into catweasel territory (albeit with the 
> convenience of an external device).

Speaking of the Catweasel, does anyone know what the data it returns actually 
means? Is it a 'time from last transition to this one' value, or something else?
(I've read the programming specs, and they're about as clear as mud)

> out how to program a PIC. I would have absolutely no idea what to do 
> with an FPGA, let alone be able to contribute anything to the design :)

Verilog isn't particularly hard to learn, especially if you know C.

>  From the point of view of the host machine, the set of operations 
> needed isn't complex - something like 'assign parameters', 'read track', 
> 'write track', 'get error information', 'format track', 'seek', and 
> possibly something like 'download firmware'. It shouldn't actually be a 
> complex device - but it is best left to someone who has experience of 
> building SBC-like devices :-)

That'd be me then.

> Transfer speed is a huge headache - 200KB or whatever at RS232 speeds is 
> painful. Repeat for 160 tracks and it becomes rather annoying! (It 
> suggests that some sort of simple compression scheme is needed)

Maybe have 115200-baud RS232 and multi-megabit USB as an option?
Add a jumper to the board to switch between them - one position for RS232, the 
other for USB.

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