Path: utzoo!attcan!uunet!tut.cis.ohio-state.edu!ucbvax!agate!shelby!portia!roadman From: roadman@portia.Stanford.EDU (arthur walker) Newsgroups: comp.sys.amiga.tech Subject: Re: Accelerating an XT Bridgeboard. Possable? Summary: accelerating 2088 Message-ID: <4455@portia.Stanford.EDU> Date: 13 Aug 89 01:48:35 GMT References: <196@stpl.UUCP> Sender: arthur walkerOrganization: Stanford University Lines: 37 In article <196@stpl.UUCP>, peterc@stpl.UUCP (Peter CAMILLERI) writes: .. > Is it possible to use a PC style accelerator card to give his machine at > least crawling pace speed? The card he is considering is the SOTA 286i, > but we would welcome discussion on any experiences anyone would have to > offer. I don't think the SOTA will work. In general, those for which you must remove the 8088 won't work, and that's almost all of them. I have an ORCHID turbo286e, which simpply plugs in on the bus, and it works. The 8088 boots while the 286e does its POST and waits. A device driver is loaded on the 8088 system and in AUTOEXEC.BAT, the user is given the choice of whether to reboot to the 286. If so, a TSR is loaded which allows/commands the 8088 to handle i/o requests via its own bios routines (from rom and PC.BOOT), which the 286 might not do as well. Any memory below the TSR and above the resident portion of MSDOS is used as a disk ram cache for the 286. A 64k segment is shared between the machines, and care must be taken in installation to avoid collisions between it and the janus memory. The 286 is fed its dos, and it loads a driver which makes all its bios calls get passed to the 8088. Writes return immediately. From the DOS prompt one can move from one machine to the other; 286->88 means that the disk cache gets flushed. The installation program allows lots of tuning. Applied Reasoning makes 286 and 386 cards that act likewise. BTW, the 286 cards cost more new than a tradeup to a 2286 would, but you can occasionally find them cheap enough for it to make sense, if you have PC slots to spare. > Peter art walker roadman@portia.stanford.edu