Date   : Thu, 21 Mar 1991 20:48:49 EDT
From   : Alexandre Montaron <MONTARON%FRP8V11.BITNET@CUNYVM.CUNY.EDU>
Subject: About Amstrad' Bios bug |

Hello|  I'm happy (in fact no) that someone else has found the bug...
 which replace a good sector (a CPM's block of 128 bytes) by anything else...
But if you typed ^C (equal to Bdos fnct number 13) it will work perfectly|

I thought it is  because of my ram-disk (DK'tronics 256Ko)... because one of
 my friend has a CPC w/o ram-disk and all work well| I've a clue about the bug
 All read & write disk access pass throught buffer (see BCB=Buffer Control Blk)
 There's at all 32Ko of buffer (as tou can call cache disk|) located on bank
 number 2 if i remember well. If the patch of the ram-disk alter this area it
 will bug when CPM attempt to save this block (perhaps it's the patch itself|)
 Because ^C flush (but not save) all buffer to disk...
 I think the answer is near | Make a list of BCB, search buffer & verify
 content of all buffer... to solve the bug you have to minimize buffers...
 It's my opinion... What do YOU thing of this ?

I've the OPERATOR's AND PROGRAMMER's GUIDE for the AMSTRAD CPC6128 & PCW8256
by Digital Research Inc. & Amstrad Consumer Electronics plc... it's a very
good book but it doesn't talk about the BIOS... and BCB (buffers) are manage
by the BIOS (see also DPH=Disk Parameter Header... which contain a pointer to
the first BCB...) I've an other book which talk about the BIOS but it's very
short |
Does someone have a better book which talk about programming (not using|)
 CP/M+ include BIOS part please... Thanks...

I hope i've forgetten anything...   Alex Montaron <MONTARON@FRP8V11.BITNET>