EISA backwards compatible?

[pentium]

I finally am kissing goodby to my 98 server and saying hello to a new dual-pentium pro AST server with 256 mb ram, windows 2000 server, a nice PCI adaptec scsi card and no on-board IDE support. The only thing I am concerned of is the use of EISA sockets with ISA cards. My ditto dash card is needed for my tape drive yet it needs an ISA port and the same goes for another controller card. I am looking around and I get mixed results:

-ISA cards will not work in EISA slots.
-ISA cards will work in EISA slots.

You guys have been around longer than me, what is the truth?

[Topcat]

Re: EISA backwards compatible?

You have 3 different selections of ISA slots, one is a short black one, which is an 8-bit ISA (most common in 286's, 386's, and early 486's), and the longer black one, which is a 16-bit ISA (common in 486's all the way through P3 and K7 PC's), and then the EISA which is a 16-bit ISA with a goofy looking PCI looking slot behind it, which used a long-ass boat ore looking card, which were commonly found in servers that had proprietary SCSI add-ons, or RAID controllers. A 16-bit card should work in that if memory serves me right.

A 16-bit card won't work in an 8-bit slot, but an 8-bit card will work in a 16-bit slot.

[Spacedye69]

Re: EISA backwards compatible?

Yup, it should work. Its like 16 bit and 32 bit Microchannel, one is longer than the other, but short card works in long slots. PCI is the same, 66 just has a little extra slot at the end.

[pentium]

Re: EISA backwards compatible?

ummmm...
I know the differences between 8 and 16-bit ISA Topcat. I was just asking if a standard 16-bit ISA card would fit into the 32-bit EISA socket.

Here is a pic of the board I got, minus the cpu and memory riser
The three slots in question are on the left of the board.



EDIT: Note what kind of caps are being used. These ones look much nicer than cans.

[Topcat]

Re: EISA backwards compatible?

Oopsie, I confused EISA with something else, my bad. No, a 16-bit card won't fit in that.

[pentium]

Re: EISA backwards compatible?

It won't?
*sigh*

[Rainbow]

Re: EISA backwards compatible?

ISA cards should fit and work in EISA slots.

[Spacedye69]

Re: EISA backwards compatible?

link SUPERSET of 16bit ISA, EXTENDS to 32bit

[pentium]

Re: EISA backwards compatible?


Thanks man!
When doubt, use wikipedia.

[gg1978]

Re: EISA backwards compatible?

Yup, you can use ISA cards in EISA slots.. The EISA slots have a "lower" section where the actual eisa signals are.. An EISA card has an extra "tongue" of connectors below the regular ISA ones.. It's keyed to allow ISA cards only to slot into the connector far enough to connect to the ISA part. If it went any further in, you'd probably short the EISA bus as the EISA section uses finer pitch for connections.. . Now how well resource management on an EISA bus works differently than ISA, not sure whether the same procedure applies.. My only EISA system is long retired.. *Compaq Pentium 60 Desktop*


On a side note, you do realize that motherboard isn't ATX??? It almost looks like it, but the screw holes appear to be in the wrong places..

[kc8adu]

Re: EISA backwards compatible?

some(most) eisa boards need a utility to register the cards.
hope those sm lytics arent bad.that would be very time consuming to recap!

[pentium]

Re: EISA backwards compatible?

The board's in pretty good shape. In fact it was never put into service. I understand it's not atx but I can live with AT for a while longer however I am worried about that secon set of power sockets. What do they exactly do? I really don't think I will even be using EISA anyways. My scsi card and network card are both PCI and PCI is far faster then EISA.
For a case fit...I might be chopping up a full-height case.

[Topcat]

Re: EISA backwards compatible?

link SUPERSET of 16bit ISA, EXTENDS to 32bit

I didn't know that about EISA either. I think I've only seen maybe one or two of them.... Sure didn't look like a 16-bit ISA would fit that goofy looking slot...

[Rainbow]

Re: EISA backwards compatible?

I also have one board with EISA slots - it's Intel dual socket 7 server board. It works but all external connectors (including keyboard) should be on a daughter board which I don't have. The card's connector looks like SIMM slot (pinout is described in board manual) - so I'm thinking about modifying a SIMM module - removing the chips, drilling the holes that connect pins on both sides and soldering 4 wires to a glued 4-pin block. Then a keyboard connector could be attached there.

[pentium]

Re: EISA backwards compatible?

Some daughterboards are just badly designed.
Who made the board.