Hi > Alright guys, down to business. Guess who found a 1551 disk drive > yesterday? :-) That's right, in its original box with manual and > diskettes. So far I have been unimpressed by its so-called "speed", but > perhaps that's because I'm used to 1541 fastload routines such as Datel's > Action Replay. There are a lot of native 1551 fastloaders, just ask Crown or Csory about. (...Csory was one of the most known people who developed stuff for native 1551 mode). I also remember a disk backup util which copied a whole disk image (using two 1551's) in 16 secs. > So, the question is: how fast can the 1551 be driven? I had a brief look > inside the drive (hmm, quite similar to the 1541C board) and the interface > cartridge, and I can tell you that there are 16 (sixteen!) wires between > the cartridge and the drive. So what are those mysterious coloured wires, > and how can they help us? I figure it ought to be possible to get proper 8 > bit parallel transfers, rather than the standard 3 bit (why?!?) protocol. The drive uses parallel data transfer of course. The 6523 TIA in the plug gets mapped into the Plus/4's address space (the decoding is done with the FPLA also found in the cartridge). The TIA has 8 + 2 + 2 port bits, 8 lines are used as data, 2 lines as handshake and the other 2... well, I don't know them. (The data transfer is fully synchronised. The Plus/4 Kernal doesn't even forbid IRQ while doing I/O between the drive and the machine.) How fast could it be? ...Heh, you can estimate it :-). The drive has a 2Mhz 6510T processor, and more RAM than an 1541 does (if I remember it right). You have a lot of lines, and speaking of the Plus/4, a computer which may be tricked easier to achieve fast speed than a C64. Udvozlet!, Levente -- This mail was written by user of Arachne, alternative WWW browser -- Arachne V1.40;beta 2, NON-COMMERCIAL version, http://www.naf.cz/arachne/ - This message was sent through the cbm-hackers mailing list. To unsubscribe: echo unsubscribe | mail firstname.lastname@example.org.
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