On Fri, Jan 04, 2002 at 10:58:08PM +0000, Dexter wrote: > > > On Fri, 4 Jan 2002, Peter Graf wrote: > > > PCI instead of ISA on Q40/Q60 would give you: > > > > *No* expandability under QDOS/SMS at all. > > Peter, thanks for explaining where the problem lies... > > Could you just fill things out a little for me and explain why it's such a > problem for QDOS/SMS? As I said, software isn't my strong suit, and you > obviously know your subject very well... > > What specifically is it that's difficult? Would this difficulty apply to > Linux also?
the problems are QDOS specific: - drivers can be practically written only in assembler, with severe restrictions like 64 bytes stack usage. Not many people around who have the thorough knowledge about the hardware and software to write more complicated drivers. - filesystem is hardwired into device driver. Instead of just writing a block device driver to implement a new hard disk you have to write a complete filesystem.. it has been done about 100 times. SMSQ has some way of solving this but nobody except TT ever went this route so nobody can say how (if) it works. Judging by source fragments and disassembly it is rather messy, even simple things like partitioned harddrives are a disaster. To be fair, all QDOS/SMSQ filesystems are long overdue to be scraped. There are jewels like maximum 65535 files per drive, maximum name length (including directory path) 36 chars and complete and useless incompatibility with anything else on the planet. Unfortunately the OS interface in both QDOS and SMSQ still has severe limitations, practically enforcing the 36 chars limit. - neither QDOS nor SMSQ are available with source. If you write eg an PCI bus initialiser the OS must have hooks to execute the code very early. Both QDOS and SMSQ have some way to do it but eg the SMSQ way appears very cumbersome. It would work somehow by linking the code into SMSQ which seems like a nightmare (for all parties) to get the distribution and copyright somehow correct. For QDOS the situation is a bit easier, disassemblies of various versions are around, QDOS Classic is even available in source, it lacks a few important features though. The biggest problem is lack of leadership - sort of. TT may or may not do anything and nobody else is willing to take the risk of inventing something new that would be incompatible with something else TT might ever develop. Bye Richard
