dyer@spdcc.COM (Steve Dyer) (10/16/87)
In article <164@uport.UUCP>, jmsully@uport.UUCP (John M. Sully) writes: > As far as a board to plug into your AT which allows it to run 386 UNIX, > the Intel InBoard (?) is one of these, it is known to run Microport. > I have talked to some customers of ours who have tried out this configuration > though, and they have found that (surprise!) it runs SLOWER than the stock > AT into which the board was placed. With the price of this board near > 2K, I'm not so sure that it is worth the probable problems when a 386 > based clone can be had for not much more (I've seen some advertised in > the Bay area for 2.2K or so). You'd think that someone who is a technical support person would know what's going on here. This is a total misrepresentation of the Intel Inboard, which I heartily recommend, at least to true IBM AT owners (some clones are tested, but the umbilical cable into the 286 socket may not reach or may not fit in an arbitrary clone.) It also can be got for a lot less than $2K. The Intel Inboard powers up at 8mhz, with cache enabled, presumably for compatibility with weird DOS programs which don't expect a speed increase (perhaps also to handle the version of the AT BIOS which tests the speed and won't boot if it's > 8mhz.) It is distributed with a DOS program which can switch the processor between 8 and 16 mhz and turn the cache on or off. This is accomplished by poking two IO ports. Unfortunately, any UNIX system which does not have special code for the Inboard will come up in 8mhz mode, which will have only a marginal speed increase over a comparable 286, discounting the speedup seen with 32-bit code generation. When I got my Inboard, I called Intel for the information on how to do the pokes myself, and then wrote a little device driver which I invoked in /etc/rc. Not a month later, SCO XENIX 386 had built-in support for the Inboard, so that the machine will boot up in 16mhz/cache-on mode--simply add the keyword "inboard" to the line defining DEFBOOTSTR in /etc/default/boot. On my 386 Inboard system for example, I get a rating of approximately 4970 Dhrystones on 1.1, which is similar to many of the clones. I highly recommend that Microport call Intel for the information on how to set the Inboard for highest performance. If you ask, I'll send you my driver, which should work just fine under Microport UNIX, although it was developed for XENIX. By the way, Intel will also perform an ECO for the board to power up at 16mhz/cache-on. -- Steve Dyer dyer@harvard.harvard.edu dyer@spdcc.COM aka {ihnp4,harvard,linus,ima,bbn,m2c}!spdcc!dyer