dnewhous wrote:

First, a question. Do 8 bit ISA cards work in 16 bit ISA slots?

Yes, they do. The 16 bit ISA slot has two connectors: the first one is the original 8 bit connector and the second one provides the upper data lines and extra control lines. An 8 bit ISA card installed in a 16 bit slot would simply use the first connector and should work without problems.

dnewhous wrote:

Were 16 bit ISA slots referred to as "EISA"?

No, EISA is a 32 bit bus introduced in 1988 by a bunch of PC manufacturers as an alternative to IBM's proprietary Micro Channel bus (MCA). EISA slots use two connectors that resemble a 16 bit ISA slot, except that the connectors are taller and have two rows of connectors. The upper row has the same signals as the original ISA slot, allowing ISA cards to be installed in EISA slots. The second level is used only by EISA cards and provide a wider data path and extra control signals for things like bus mastering and faster data transfers.

dnewhous wrote:

Was there ever a 486 motherboard that had VESA 2.0 support and the ability to support a CD-ROM via IDE connection (i.e., not through the sound card)?

Are you sure that you are not confusing the VESA standard for video cards with the VESA Local Bus (a.k.a. VL-Bus) standard for expansion slots? We usually refer to the video cards as "VESA 1.2", "VESA 2.0" or "VESA 3.0" according to the spec version they support. When we talk about motherboards we usually use the name VESA (without a number) referring to VL-Bus slots. VL-Bus is a local bus based on the 486 processor bus and was quite common in 486 motherboards. It was designed by the VESA group as an alternative to the slower ISA bus and the more expensive EISA bus. Since VL-Bus was intimately tied to the 486 architecture, it vanished soon after the introduction of the Pentium processor and the PCI bus.

Finally, I remember a few 486 motherboards that included E-IDE controllers that supported CD-ROMs, although such controllers were not standard at the time. They became a standard in Pentium-based motherboards.

Regards,

I was thinking there was a VESA slot on DOS machines in addition to ISA slot much like modern AGP/PCI duality. I probably am confused.

No, originally there were just ISA slots. Then something quicker was needed, so IBM introduced MCA (patented, so it could not be used by other firms). Others came with EISA (backward compatible with ISA).
Both MCA/EISA were used mainly in industry, they were not very widespread. Average users kept ISA.
Then the problem appeared with ISA being too slow for newer graphic cards, so VESA was introduced (at the time of 80486). Short time later PCI appeared. It quickly ended era of VESA. There were already some PCI motherboards for 80486, for later processors I think only PCI was ever used. Unlike VESA it was universal bus (not only for graphic cards)
A few years ago also PCI became too slow, so AGP was introced (increasing speed 1*, 2., 4* 8*).
At the moment PCI-X is being slowly introduced. It is a universall bus, it should replace both PCI and AGP.

Mirek

mirekluza wrote:

Then the problem appeared with ISA being too slow for newer graphic cards, so VESA was introduced (at the time of 80486). Short time later PCI appeared. It quickly ended era of VESA. There were already some PCI motherboards for 80486, for later processors I think only PCI was ever used. Unlike VESA it was universal bus (not only for graphic cards)

The way you say this is confusing. Do VESA cards use ISA slots (16 bit presumably)?

At the moment PCI-X is being slowly introduced. It is a universall bus, it should replace both PCI and AGP.

No, PCI-E is replacing PCI for desktop users. PCI-X is for dual processor boards/Itanium. They don't call it "AGP" anymore but the video card still gets a special slot. The standard PCI-E slot is tiny, the PCI-E slot for the video card is the same size as the old AGP slot and goes 16 times as fast the regular PCI-E slot.

dnewhous wrote:

The way you say this is confusing. Do VESA cards use ISA slots (16 bit presumably)?
....
No, PCI-E is replacing PCI for desktop users. PCI-X is for dual processor boards/Itanium. They don't call it "AGP" anymore but the video card still gets a special slot. The standard PCI-E slot is tiny, the PCI-E slot for the video card is the same size as the old AGP slot and goes 16 times as fast the regular PCI-E slot.

VESA was not compatible with ISA. It had its own connector. It was not compatible with anything else.

PCI-X, PCI-E stuff: I did not check it much, so you may be right... The one thing I remember was the fact that it should replkace both AGP and PCI. But it is possible that they will make a slot for graphic card physically bigger .... Graphic cards are big nowadays. 😀

Mirek

mirekluza wrote:

VESA was not compatible with ISA. It had its own connector. It was not compatible with anything else.

Mirek

So a VESA motherboard wouldn't have any ISA slots?

May I suggest that a hour or two spent with Google would suffice?

An old article: http://www.mycableshop.com/techarticles/slots.htm

VESA (or VESA Local Bus) slots were in addition to 16bit ISA slots. Manufacturers did this so that they didn't require all add-in cards to be thrown in the skip. Same for when PCI was introduced. For a couple of years, motherboards continued to have ISA slots fitted although these have pretty much gone now.

VESA was at the time something like AGP today (graphic card only as far as I know). There were normal ISA slots as well.

So graphic cards evolution went like this:
ISA
VESA
PCI
AGP

Evolution of slots for others cards was simpler:
ISA
PCI

BTW: I have still ISA slot in my motherboard (ABIT something, 1 Ghz Athlon, 2 or 3 years old). Of course I have PCI and AGP as well. I specifically wanted such motherboard. I have two sound cards (ISA SB compatible and PCI SoundBlaster live). Good thing for old DOS games ... 😀.

Mirek

VESA Local Bus was not only for Graphic Cards:
http://www.faculty.iu-bremen.de/birk/lectures … ges/road_04.jpg

http://members.iweb.net.au/~pstorr/pcbook/ima … es/486vesa1.jpg

http://www.alltheweb.com/search?cat=img&custi … =vesa+local+bus

btw - I also have a motherboard with one isa slot and i can use it even with athlon 2400+ 😀 (I have duron 1400 right now)

Indeed, I had a VL based mobo with a 486 DX4/100 IIRC!! I had an Adpatec VL-Bus SCSI card and an Avance Logic VL-Bus graphics card!

Funny but it was probably Intel based mobos that dropped ISA faster whereas it would seem that the AMD systems kept support for it longer (I remember giving a friend of mine my last ISA card - modem - when I upgraded!). My old Pentium system (P3-500) still has a single slot which I had my old AWE-64 card in it!. Musical chairs this upgrade thing 😀

dnewhous wrote:

I was thinking there was a VESA slot on DOS machines in addition to ISA slot much like modern AGP/PCI duality. I probably am confused.

No, you are right. Several 486 motherboards had the usual ISA slots and two or three VESA local bus (VL-Bus) slots. Remeber: VL-Bus slots were actually ISA slots with an extra, larger connector, for the local bus signals.

Did all desktop 486s support VESA or were some ISA only?

My 1st 486 was ISA only, my 2nd was ISA & VL-BUS and the last I had dealings with (I didn't own this one!) was ISA/PCI 😀 I can't remember too much about each except it was quite a period of change (and therefore cost!).

Just a clarification..

PCI-Xtended is not just for dual processor system. I seen many single processor and quad processor systems have them. in fact, my quad 940 tyan has two independent PCI-X busses. Perhaps you should have said workstations and servers. :p

PCI-X and PCI-E(xpress)/3GIO are not the same, as has been said before.

For the curious, the almighty wikipedia.
http://en.wikipedia.org/wiki/Peripheral_Compo … nt_Interconnect

This post is probably superfluous, but I just completed a 28kpoly creature and have nothing better to do.

The original 8-bit slots did not actually have an official name; most people I know just called them PC slots or expansion slots. The term ISA (Industry Standard Architecture) didn't come around until the 16-bit slot was developed. There are some 16-bit ISA cards that will work fine in 8-bit slots; I have a CGA card that will work in either. Just some useless trivia. 😀

PCI-X is 64bit PCI slot. AFAIK it's mostly used in servers where gigabit lan and fibre cards require more bandwidth.
PCI-E is the new slot and the difference from all previous expansion slots is that it's no longer a bus. Where in PCI world all cards share PCI bandwidth (132MB/s), each PCI-E card has it's own data lane. PCI-E slots used for graphics cards are bigger since they have enough connectors for 16 simultaneous lanes, while normal slots have only 1 channel. Unlike AGP, 16x PCI-E is not limited to graphics card only (but try to find a card that requires 16x...a singe lane can transmit data at 2.5Gbps more than 2x speed of the whole PCI bus). Another difference is that all previous buses were parallel (hence 32-64bit differece in PCI & PCI-X) and PCI-E is serial (compare this to ATA and SATA).

As for 486 systems, it was already said. You could get ISA only, ISA/VLB and ISA/PCI motherboards (and if you really tried ISA/PCI with 1 VLB slot motherboard 😀). The newer ISA/PCI motherboards also frequently had an integrated IDE controlled (which many people take for granted today), so yes, you could hook up a CD-ROM to it (but here you had to be careful, CDROM unit also had to be ATAPI standard). And if somebody is wondering - I have a VLB E-IDE controller still stacked somewhere 😁

One good thing is that PCI-E will replace PCI-X as well as PCI, and AGP

This means power gamers will eventually be able to get server class raid cards without concern about compatibility. =D I await that day.

Hahahaha, ribbon13, you are so hopeful. I wish I could be that optimistic. I'm afraid my dreams of a really powerful RAID card working to its full advantage is still going to be a pipe dream.

Really now? I have already seen prototype 1x PCI-E controllers using the SiI 3132. The big factor now really is just time. There are no Athlon64/Opteron chipsets supporting PCI-E in production. Just prototypes, alphas, and press announcements... But soon, they will be out on the market.

The real pipe dream of mine is a dual/quad processor board with 2 16xPCI-E slots, which probably isn't gonna happen.

2 processors and 2 graphics cards.... How much ass would that kick?