On 2013-09-16, at 18:21, Ruud@Baltissen.org wrote: > I received a huge bag full of diskettes for the CBM that I want to turn into images. For this purpose I use a PC with a self built IEEE interface. The PC tells the drive to send the sectors one by one and it creates the image out of them. But it takes about 20 minutes to copy a 8250 disk. And that is faster than what a 8032 could do! > > If not, could anybody give some pointers/ideas where to think of when writing one myself. With 1541 and Co. the first thing is to overcome the slow serial comms. But IEEE is parallel, isn't it. Hence the reason for it being so slow need to lie elsewhere. With parallel connection I am aiming at getting below 20 seconds for a full image on a 1541. If I can do it on a 64 and 1541 - similar times should be achievable on IEEE, unless there are some limitations I am not aware of. > I just realise that maybe some software has to be written that must run on the drive itself, just what Star Commander does. One lucky thing: 4040 disk can be read by SC, 3040 disks are very rare and 8050 disks can be read by the 8250 as well so we only have to focus on the 8250. > Any info, comment, ideas, etc. are welcome! Once the serial communication is out of question, the next thing is to get the data as fast as possible off the disk. The easiest way is to put each track into buffer in one revolution - the way I do with DolphinDOS - but if one doesn't have enough RAM to buffer the whole track, the next option is to keep a table of sectors already processed and getting each next sector whenever it comes and had not yet been processed. This is the way I do without having DolphinDOS installed. For clarity - I haven't invented this. It is used in various parallel copiers for decades ;-) Hence I'd suggest: 1. Checking if IEEE can be used in similar way (and speed) as IEC with parallel connection attached (probably yes) 2. Checking if there is enough RAM to hold the whole track (probably not - I don't remember 8250 specs) 3. Implementing both sides I assume you will store the images on the PC - what is your connection to the PC? What are its limits? -- SD! Message was sent through the cbm-hackers mailing listReceived on 2013-09-16 18:00:09
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