nicolas@cli52or.edf.fr (05/02/91)
hi all can someone here explain me what are the differences between the 386sx and the 386dx, concerning Bruce Evans 32-bits kernel ?? sorry if this has already been explained thank you all nicolas
Christoph van Wuellen <HBO043%DJUKFA11.BITNET@cunyvm.cuny.edu> (05/02/91)
for the software, that is the same, the sx has a 16-bit bus interface and a smaller prefetch queue. C.v.W.
nicolas@cli52or.edf.fr (05/02/91)
> > for the software, that is the same, > > the sx has a 16-bit bus interface and a smaller prefetch queue. > > C.v.W. > 16-bit bus interface : does this means that the segment's size of a process is limited to 64K ?
drp@buhub.bradley.edu (Douglas Pokorny) (05/03/91)
nicolas@cli52or.edf.fr writes: >16-bit bus interface : >does this means that the segment's size of a process is limited to 64K ? Nope, externally the 386sx has a 24-bit address bus and a 16-bit data bus. Internally the 386sx has 32-bit registers and the same 64-terrabyte virtual memory management hardware as the 386dx. As previously mentioned, the only differance between the 80386dx and the 80386sx are: Physical packaging/size (sx is a gull-wing flat-pack, dx is a PGA device) Size of the the external addressing lines -- 16-bit data -vs- 32-bit data and 24-bit address -vs- 32-bit address. Size of the instruction pre-fetch queue. There technically isn't ANY software which will run on a 386dx that won't run on a 386sx. I just wish that computer salesmen and the idiots in the world would get that through their heads. The only software which will operate differently is one which tries to check the pre-fetch queue size. Source code for this is on Simtel20. This however is NOT normal "run-of-the-mill" programming, and anyone who would use the above to limit the processors on which their software will run has got to have a serious mental deficiency. -Douglas _________________________________________________________ ________ ___ ___ |_ __ \ | | | | Douglas R. Pokorny | |__| / | | | | drp@buhub.bradley.edu | __ \ | | | | CS major/Geisert Hall Resident _| |__| | | \__/ | The best of both worlds! |________/ \______/ Bradley University "The Harvard of the Midwest"
HBO043%DJUKFA11.BITNET@cunyvm.cuny.edu (Christoph van Wuellen) (05/03/91)
no,no, a 16-bit bus interface has nothing to do with segment sizes, I stated: for the software, there is no difference. 16-bit bus interface means: The storage is 16-bit wide, thus two bus cycles are necessary when accessing a 32-bit word in memory. This is very much like the 68000 does it. C.v.W.
nicolas@cli52or.edf.fr (05/06/91)
Hello *, ok thank you all for responding . i understand there is no difference between 386sx/386dx except for the bus (24-bit addresses and 16-bit data). with a 386sx, is it possible to add memory with a card plugged in the bus ? i know it is possible, but how that memory will be addressable : - real memory - expanded memory - extended memory - ??? in other words, suppose i buy a 386sx card with , say 4 Mb of ram on it, will i be limited to 4 Mb or can i add real addressable memory up to XX Mb (XX = ?) with additional card(s) ?? nicolas
HBO043%DJUKFA11.BITNET@cunyvm.cuny.edu (Christoph van Wuellen) (05/07/91)
That depends on your card if you can add memory. If you have an AT bus with 16MByte address space, it should be possible to add memory cards for your 386sx. However, since the AT bus is not the fastest bus in the world, it is generally better to have all memory on the CPU card, thus accessible without mangling the data through the bus. C.v.W.
peter@pa3ebv.nl.mugnet.org (Peter J. de Vrijer) (05/07/91)
In article <52442@nigel.ee.udel.edu>, nicolas@cli52or.edf.fr () wrote: >> >> for the software, that is the same, >> >> the sx has a 16-bit bus interface and a smaller prefetch queue. >> >> C.v.W. >> > > 16-bit bus interface : > does this means that the segment's size of a process is limited to 64K ? No it just means that to get 32 bits from memory the sx has to do 2 memory reads and thus is slower than the dx. Regards from Peter. Peter J. de Vrijer | UUCP: peter@pa3ebv.nl.mugnet.org Tel: +31 38 660735 | packet radio: peter@pa3ebv.ampr.org Ministerlaan 9 | 8014 PL Zwolle | "And yet I'm happy, The Netherlands | I can't figure it out." Snoopy