Jump to content

syscall

Members
  • Content Count

    2
  • Joined

  • Last visited

Community Reputation

0 Neutral

About syscall

  • Rank
    Combat Commando
  1. OK, nevermind, seems that I was mistaken. Putting percom block to the drive seems not to mean reconfiguring it at once. It's needed for other commands that will come later. Drive should not switch densities JUST after writing percom to it. It's a parameter block for other commands, not a command itself. No?
  2. Hey, Until now, my understanding of the PERCOM block (and send percom command) was that this block configures the drive with selected parameters. If any of the parameters is wrong, percom block is discarded. If parameters match one of the drive's densities, they are set hard, until next put percom. So after setting the drive to FM with put_percom command, the drive sits there in FM until commanded otherwise by another PUT PERCOM. Is that understanding OK? Now, mydos. If configuration is read by percom, and not by get status, Mydos does not see the difference between SD and ED other way than by sectors per track number. FM/MFM flag is discarded. So if you have ED disk, and boot mydos off it, the percom block that is sent to the drive is for the FM/ED (which is wrong). So the dos cannot read DUP.SYS because the drive is already in FM and the disk is ED. Perhaps FM/MFM flag ( Percom[5].bit2 ) in PERCOM should be discarded? I don't know, it's there for a reason. How does the original PERCOM drive handle this? Regards
×
×
  • Create New...