13 Oct
2000
13 Oct
'00
3:39 p.m.
From: Jerome Fine <jhfine(a)idirect.com>
I doubt very much that the answer is YES! Otherwise,
it would have been
easy to produce the 3rd party SCSI host adapters and there would have
been a lot more competition - even with the $ US 100 license fee.
the key is not to design a VMS driver so MSCP makes you immune to that.
If your willing then a bare SCSI interface is very doable, but the driver
will
be harder and slower even with DMA. In VAX products there was
competition
around storage perfomance even back then.
Now I have heard of someone attempting to produce a
Qbus controller
for an IDE drive that would not even be MSCP - and probably put the
IDE drive right on the controller - not that MSCP would be all that
There is a design out there, crude and PIO only. It would certainly work
as IDE can PIO pretty fast. the only thing that makes Q-bus the least
bit
hard is that it has a read before write, that can mess up some register o
riented devices with an out of sequence read.
Allison