A flash adapter of this type is only economical is high volume. The BOM and assembly costs in low volumes are higher than the cost of a off the shelf motherboard unless you plan on building them yourself and your time is of no or little value.
A design to page out flash memory into a small space in memory is done the way Expanded Memory was done for the old IBM-PC via page frames. Here's an example of how it could map into system memory: PC MAIN MEMORY LIM EXPANDED MEMORY -------------- ------------------- +-------------+ | | . Extended . . Memory . . up to . /+-------------+ 32M . 16M on the . // | | . '286, . / / | | . 4096M on . / / | Expanded | . the '386 . / / | Memory | | | / / | | 1M +-------------+ / / | Divided | | | / / | into 16K | 960K +-------------+ / | logical | | Page Frame | / | pages | | 12*16K | / | | | Physical | / | | | Pages | / | | 768K +-------------+\ / . . | | / . . 640K +-------------+/ \ . . | Page Frame | \ . . | 24*16K | \ | | | Physical | \ | | | Pages | \ | | | | \ | | 256K +-------------+ \ | | | | \ \ | | | | \ \ | | | | \ \ | | 0 +-------------+ \ \ | | \ \ | | \ \ | | \ \| | \+-------------+ 0 The example shows how expanded memory gives you up to a 32M to map into up to 36 16K pages in the positions shown above. If anyone wants schematics I can dig through some Orcads from the 80's and pass em along ;) Bari Jan Kok wrote: >Hamish, what would you use for a plug to plug into the BIOS socket? I >searched all over the place for a plug (or PLCC to DIP adapter for DoC) and >didn't find anything useful for less than about $60 small quantity -- except >for the Bios Savior device (about $30 from www.mwave.com). > >- Jan > >----- Original Message ----- >From: "Hamish Guthrie (Mail Lists)" <[EMAIL PROTECTED]> >To: "Ronald G Minnich" <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]> >Sent: Monday, September 09, 2002 4:03 AM >Subject: RE: The DoC problem > > > > >>I think the DoC mess is here to stay, there is one potential solution if >>people are insisting on having DoC, and that is to make up a little board >>which plugs into a BIOS socket which has both a 256k flash device and a >>little bit of decode logic for a DoC, as well as a DoC - if anyone is >>interested in this approach, I could knock together a few prototypes for a >>couple of $'s, but I have my reservations as to this being a permanent >>long-term solution for production systems. >> >>Hamish >> >> > > >_______________________________________________ >Linuxbios mailing list >[EMAIL PROTECTED] >http://www.clustermatic.org/mailman/listinfo/linuxbios > > > > _______________________________________________ Linuxbios mailing list [EMAIL PROTECTED] http://www.clustermatic.org/mailman/listinfo/linuxbios
