sjs@gnv.ifas.ufl.edu (03/29/91)
In article <14111@hacgate.UUCP>, tackett@ipla01.hac.com (Walter Tackett) writes: >i am buying an ibm pc clone with a 33MHz 80486 processor. the dealer says >that it sports an ISA (as opposed to an EISA) bus architecture. Is this guy >full of sh*t or does it make a critical difference, or what? my understanding >was that ISA is basically a 16-bit bus structure! RSVP FAST! Please include >any references to published material which may be of use to me. Thank you >in advance. >-walter >tackett@ipla01.hac.com >sahtirn@ipla01.hac.com ISA is Industry Standard Architecture, which is like what the IBM AT had, a bus that could handle 8- and 16-bit cards. EISA is Extended ISA and is downward compatible with ISA cards. An EISA slot can take a 16-bit ISA, or an EISA-specific 32-bit card (the EISA card has a special edge). So, the difference between ISA and EISA is the ability to use 32-bit EISA cards. (An EISA PC may also have slot(s) for 8-bit cards, I forget; but ask the dealer). You should get 8- and 16-bit slots, as that is what is required by most cards, like hard/floppy, VGA, COM/LP, scanner cards, etc. You don't really need a 32-bit slot unless you have a card in mind that uses it, or wish to have it for potential future use. But then again, the 32-bit slot can always take a 16-bit card. For myself, and for my own use, I might get one with one EISA slot just in case I wanted a card that required it, but I wouldn't bother with a PC that had more than one EISA slot. EISA first came out in 1989, so check PC mags dated with that year.
ntaib@silver.ucs.indiana.edu (Nur Iskandar Taib) (03/31/91)
>ISA is Industry Standard Architecture, which is like what the IBM AT >had, a bus that could handle 8- and 16-bit cards. EISA is Extended >ISA and is downward compatible with ISA cards. An EISA slot can take >a 16-bit ISA, or an EISA-specific 32-bit card (the EISA card has a >special edge). So, the difference between ISA and EISA is the ability >to use 32-bit EISA cards. (An EISA PC may also have slot(s) for 8-bit >cards, I forget; but ask the dealer). I suppose it would be useful to mention that most 386DX and 486 computers with ISA buses also have 32 bit slots. These slots are usually used for memory expansion, and are pro- prietary. Come to think of it, is there a "standard" 32-bit memory expansion card that fits in the slots of large numbers of clone motherboards, or does EVERY motherboard have its own proprietary 32-bit card? I suspect there are 3 or 4 widely used cards and slots that are shared by several manufactur- ers. (I remember giving a Zenith sales rep a really hard time because she insisted the 32-bit slots in their machines was ISA). -- ------------------------------------------------------------------------------- Iskandar Taib | The only thing worse than Peach ala Internet: NTAIB@AQUA.UCS.INDIANA.EDU | Frog is Frog ala Peach Bitnet: NTAIB@IUBACS ! -------------------------------------------------------------------------------
cctr132@csc.canterbury.ac.nz (Nick FitzGerald, CSC, Uni. of Canterbury, NZ) (03/31/91)
In article <1991Mar30.222106.28919@bronze.ucs.indiana.edu>, ntaib@silver.ucs.indiana.edu (Nur Iskandar Taib) writes: [somebody else wrote the first bit, but Iskander hasn't attributed it] >>ISA is Industry Standard Architecture, which is like what the IBM AT >>had, a bus that could handle 8- and 16-bit cards. EISA is Extended >>ISA and is downward compatible with ISA cards. An EISA slot can take >>a 16-bit ISA, or an EISA-specific 32-bit card (the EISA card has a >>special edge). So, the difference between ISA and EISA is the ability >>to use 32-bit EISA cards. (An EISA PC may also have slot(s) for 8-bit >>cards, I forget; but ask the dealer). An EISA PC _can_ have 8-bit only and 16-bit only slots, or all EISA. > I suppose it would be useful to mention that most 386DX and > 486 computers with ISA buses also have 32 bit slots. These > slots are usually used for memory expansion, and are pro- > prietary. > > Come to think of it, is there a "standard" 32-bit memory > expansion card that fits in the slots of large numbers of > clone motherboards, or does EVERY motherboard have its own > proprietary 32-bit card? I suspect there are 3 or 4 widely > used cards and slots that are shared by several manufactur- > ers. I don't know if there is some sort of standard or not, but I recommend anyone who buys a 386 that if they have the slightest inkling that they may _someday_ want more RAM than fits on the motherboard, they should obtain a 32-bit memory expansion board with their PC. These usually take SIMM's (sometimes SIPP's or just chips) which can be easily purchased later (they are much more likely to be available in 3-5 years than the correct expansion boards). Generally you are looking at an extra NZ$120-150 (US$65-80 ?) which is money well spent in my books. I know two people who bought cheap-ish 386 clones a couple of years ago, and whilst the outfit that sold them is still in business, still selling what look like the same machines, they have different m/b's and the RAM expansion cards for these are incompatible with their m/b's. The suppliers claim that the cards for the old boards are no longer available as the manufacturers no longer make the m/b's so also stopped making the expansion cards. > (I remember giving a Zenith sales rep a really hard time > because she insisted the 32-bit slots in their machines > was ISA). That's mean, cruel and nasty! 8-) She was only doing her job!! 8-), 8-) --------------------------------------------------------------------------- Nick FitzGerald, PC Applications Consultant, CSC, Uni of Canterbury, N.Z. Internet: n.fitzgerald@csc.canterbury.ac.nz Phone: (64)(3) 642-337
akm@geriatrix.cs.uoregon.edu (Anant Kartik Mithal) (03/31/91)
In article <1991Mar31.182147.361@csc.canterbury.ac.nz> cctr132@csc.canterbury.ac.nz (Nick FitzGerald, CSC, Uni. of Canterbury, NZ) writes: >In article <1991Mar30.222106.28919@bronze.ucs.indiana.edu>, >ntaib@silver.ucs.indiana.edu (Nur Iskandar Taib) writes: >I don't know if there is some sort of standard or not, but I recommend >anyone who buys a 386 that if they have the slightest inkling that they >may _someday_ want more RAM than fits on the motherboard, they should >obtain a 32-bit memory expansion board with their PC. >I know two people who bought cheap-ish 386 clones a couple of years ago, >The >suppliers claim that the cards for the old boards are no longer available >as the manufacturers no longer make the m/b's so also stopped making the >expansion cards. That happened to me. Actually, I have two recommendations on this based on my experience with my motherboard. First, make sure that the SIMM slots are not in a position where add-on cards would run "across/over" them. This is where the memory sits in an AT, which is fine on an AT because DIP chips are low, but SIMMS are high, and on my M/B, the simms bump into expansion cards. Newer MB/s have the simms on the side, near the power connecter, which is much better. That way there is nothing that is supposed to go "above" them, so the height of the SIMMs is not a problem Second, instead of bothering about memory expansion, I'd suggest a motherboard that has 16 SIMM sockets, and can take 256/1MB/4MB SIMMS. THat way, sometime in the future you can have 64M without hassling about 32bit cards that you may or may not have... I wish I'd done that... Someone want to tell me if I can add a 16 bit ram card to my 386? Like the BOCA AT Plus? What happens? >> (I remember giving a Zenith sales rep a really hard time >> because she insisted the 32-bit slots in their machines >> was ISA). >That's mean, cruel and nasty! 8-) >She was only doing her job!! 8-), 8-) I hate to say this, but she might have been entirely correct. The 32 bit slot in my machine is ISA. i.e., you can stick a 16-bit ISA board into it, and that board will run just fine. I currently have my video card sitting there. The second, "AT" part of the connector is longer to accomodate the extra lines. If anyone has heard about such a 32 bit expansion card, I'm all ears. kartik -- Anant Kartik Mithal akm@cs.uoregon.edu Research Assistant, (503)346-4408 (msgs) Department of Computer Science, (503)346-3989 (direct) University of Oregon, Eugene, OR 97403-1202
ntaib@silver.ucs.indiana.edu (Nur Iskandar Taib) (04/02/91)
>> (I remember giving a Zenith sales rep a really hard time >> because she insisted the 32-bit slots in their machines >> was ISA). >That's mean, cruel and nasty! 8-) >She was only doing her job!! 8-), 8-) In self defence, I must admit I was feeling a little annoyed at her because before the presentation she had mashed a poor, defenceless spider (she said it was "invading her personal space") 8-) Actually, the whole audience gave her a REAL hard time about how Macs were so much easier to set up than the Zeniths with pre-installed Windows after she asked us if we knew what a cache was 8-) . Even the most die-hard PC Mac haters joined in 8-). -- ------------------------------------------------------------------------------- Iskandar Taib | The only thing worse than Peach ala Internet: NTAIB@AQUA.UCS.INDIANA.EDU | Frog is Frog ala Peach Bitnet: NTAIB@IUBACS ! -------------------------------------------------------------------------------
ntaib@silver.ucs.indiana.edu (Nur Iskandar Taib) (04/02/91)
>>> (I remember giving a Zenith sales rep a really hard time >>> because she insisted the 32-bit slots in their machines >>> was ISA). >>That's mean, cruel and nasty! 8-) >>She was only doing her job!! 8-), 8-) >I hate to say this, but she might have been entirely correct. The 32 >bit slot in my machine is ISA. i.e., you can stick a 16-bit ISA board >into it, and that board will run just fine. I currently have my video >card sitting there. The second, "AT" part of the connector is longer >to accomodate the extra lines. As a matter of fact, the Zenith 32-bit slots WERE 16-bit ISA compatible (they call them SmartSlots or something of the sort). The cards are, as one might expect, proprietary and not ISA. -- ------------------------------------------------------------------------------- Iskandar Taib | The only thing worse than Peach ala Internet: NTAIB@AQUA.UCS.INDIANA.EDU | Frog is Frog ala Peach Bitnet: NTAIB@IUBACS ! -------------------------------------------------------------------------------