There's a confusion between sector and cluster here. ED disks really _are_ 36 physical sectors per track. That's in the IBM spec. They should only format to 5760 physical sectors, but possibly Miracle formatted tracks beyond 80 to get the extra capacity; 88 tracks would get 6336, which is close to their quoted 6400 sectors.
Anyway, a physical sector on a floppy disk is 512 bytes, but the "cluster" size for an ED disk is four physical sectors = 2048 bytes. (So 80*20 = 1600 clusters = 6400 sectors = 3.2MB) Then, as Bob says, the issue is understanding the order in which each cluster has been mapped to the physical sectors. Adrian www.memorylanecomputing.com > -----Original Message----- > From: ql-users-boun...@lists.q-v-d.com [mailto:ql-users-bounces@lists.q-v- > d.com] On Behalf Of Bob Spelten > Sent: 09 October 2011 11:15 > To: ql-us...@q-v-d.com > Subject: Re: [Ql-Users] Making an image of an ED Disk Drive > > Op Sat, 08 Oct 2011 12:15:34 +0200 schreef Rich Mellor > <r...@rwapservices.co.uk>: > > > I am trying desparately to get the ED disk drive image working with > > the HxC floppy disk drive emulator. > > > > The ED disk drive parameters are > > 80 tracks > > 2 sides > > 10 sectors per track > > sector is 2048 bytes > > > > My BASIC code to create a copy of a disk appears below: > > > > 100 OPEN_IN #3,'flp2_*D4e' > > 105 OPEN_NEW #4,ram1_ED_img > > 107 FOR tracks=0 TO 79 > > 108 FOR sides=0 TO 1 > > 109 FOR sector=1 TO 10 > > 110 GET #3\sector+sides*256+tracks*2^16,sector$ > > 112 AT 0,0 > > 115 PRINT tracks,sides,sector;' ' > > 120 PRINT #4;sector$; > > 122 END FOR sector > > 125 END FOR sides > > 127 END FOR tracks > > 130 CLOSE > > > > Do I have this working the right way around (or should the sides loop > > be outside the tracks loop?) > > > > This does create an image of the correct size, but I can't get the QL > > to read it once converted. > > To convert it to the HxC format, I have tried a bitrate of 500000 > > (same as a HD disk drive, although this may be wrong), and an RPM of > > 300 (although I am told it may need to be 150) Interleave is also set > > at 1 > > > > Any other suggestions on where I might be going wrong? > > > DM5 confirms: 80 tracks, 10 sectors/track, 2 sides (20 sectors/cylinder, not 36 > sectors) This program is probably fine if you copy them back to a disk in the > same way. > The HxC is however not a double sided drive so you may need to get the > sectors in the right order for the ED-driver to recognise it. > > The DP Media Manager SE manual states that files are written in blocks of > 3 sectors (chapter 5). > Although this was written for DD disks it may still be useful for HD/ED. > These blocks are written as follows: (track/side/sector) > 0/0/0, 0/0/3, 0/0/6, 0/1/0, 0/1/3, 0/1/6 > 0/0/1, 0/0/4, 0/0/7, 0/1/1, 0/1/4, 0/1/7 > 0/0/2, 0/0/5, 0/0/8, 0/1/2, 0/1/5, 0/1/8 ... > So 6 blocks, 18 sectors, one cylinder, filling track 0. > > Then for track 1 to n it gets more complicated, an offset is used to find the > next sector. > (entry + (track * offset)) MOD sectors_per_track (Now it gets confusing, > MMSE states the offset =5, DM5 reports 320! And I don't get how this > works.) > > Some speculation. > As you can see sides are used in turn, as ED uses 1 sector/block this could > mean: > 0/0/0, 0/1/0, 0/0/1, 0/1/1, ... 20 blocks, filling 20 sectors. > (or 0/0/0, 0/1/0, 0/0/2, 0/1/2, ... with 1 sector interleave.) This means the > sides loop should be the inside loop. > > We need more info on how Miracle did this from Stuart Honeyball or TT or > Marcel(?). > Even info on the IBM 2.88 drive is scarce on the internet, or I am not that > fluent in Googleing. > I did find however they were used in the NeXT computers. > > Bob > > -- > The BSJR QL software site at: http://members.chello.nl/b.spelten/ql/ > _______________________________________________ > QL-Users Mailing List > http://www.q-v-d.demon.co.uk/smsqe.htm _______________________________________________ QL-Users Mailing List http://www.q-v-d.demon.co.uk/smsqe.htm
