kre@mulga.OZ (Robert Elz) (03/07/85)
In article <482@lsuc.UUCP> dave@lsuc.UUCP (David Sherman) writes: | Our local sales rep tells me that the Fujitsu 474Mb (I believe | this is the "Eagle") drive is available for P-E machines, | but that it won't run under UNIX because it (the drive) is "too fast". | This sounds rather curious. Anyone have any more info? First, allow me to possibly apologise in advance. Mulga has only just been connected to pe.cust.* newsgroups, and I'm not sure what the conventions are for using these groups. If this shouldn't be where it is, please correct me. The above extract appeared in pe.cust.wanted, that didn't seem to be the right place for a reply, but I suspect that this info may be useful enough to enough people not to just send it by mail, so I thought I'd post it here. First, a little explanation - mulga is one of the oldest PE machines to run unix, and definitely the oldest 3200 series. We don't run a PE supplied version (rather the version that ours was derived from was also the source of PE's system, both originated at the Univ of Wollongong in Australia). We just connected a Fuji eagle to mulga. Its connected to a Spectra Logic controller, but I doubt that that makes any difference, if it was on a PE IDC the following would probably still be true. Your sales rep was right, the UNIX 'msm' (or 'idc') disc driver is too slow for the eagle. When it is instructed to start a transfer the drive starts very quickly (or can do). Its likely that the unix driver has not started the selch when the controller has data ready to send (or when it requests data). This causes problems! Its the way it is because UNIX is written in C (bet you didn't know that :-) and to interface with devices small assembler routines are called. It turns out that the calling sequence takes too long. I replaced the whole "start the controller; start the selch" sequence with asm's in my driver, the eagle works fine that way. It could also be replaced with a specialized assembler routine of course. Robert Elz {decvax,pesnta}!mulga!kre ps: yes I know, I have source, you probably don't. My compiler has "asm's", yours probably doesn't ... Sorry, there's nothing I can do about that.
dave@lsuc.UUCP (David Sherman) (03/09/85)
Thanks for your comments, Robert. I don't think the volume of
traffic on pe.cust is enough yet that we have to start worrying
about where to post things; this newsgroup is fine with me.
The day after I posted my request about this, I got a call back
from our sales rep (hadn't spoken to him in several weeks, actually).
He tells me that a company called Micos in Toronto has written
a driver for the Eagle under Edition VII. He's going to find out
more about it and get back to me. When I get details, I'll post.
Dave Sherman
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