Are you trying to find a replacement/upgrade board for your really small case? Or a case for that board?

This is a half-size baby AT board. Don't think there's a specific term for it. It also doesn't have all slots populated (potentially boards could have two more slots between the top slot here and the power connector). Regardless, this would fit in any (Baby)AT case. Conversely, these boards were frequently used in very small proprietary cases, usually with a riser. To fit in there a board would need to be max same size as this, with holes in same places (not usually a problem as baby AT standard) and whatever slot is used by the riser in the same place too.

So any AT case would be fine for the board. 1-1 replacement of board should be fairly easy, most late 386SX boards were similar to these. Upgrade would be a challenge. I have a similar 486SLC, but boards with 32b external bus are rare at this form factor. Only exception are a couple of late Vtech/PCPartner boards like the VIB878DS (So7, Via MVP3-based) with AGP that can fit a K6-2 in the same form factor. That said, not much chance of fitting into the same case - that ISA riser won't fit in an AGP slot and even if the riser were at the end of the board, you still have the issue of heat production of a K6-2 vs 386SX - it would probably melt in a tiny case like some 386SX.

dionb wrote on 2024-04-02, 08:31:

Are you trying to find a replacement/upgrade board for your really small case? Or a case for that board?

Both. Although most of the boards I saw in that size are 386SX and I'd like either DX or 486.
I'm looking for a small x86 (preferably like 386 or 486). I've seen SBCs but they seem quite expensive, and usually require a backplane.

dionb wrote on 2024-04-02, 08:31:

This is a half-size baby AT board. Don't think there's a specific term for it. It also doesn't have all slots populated (potentially boards could have two more slots between the top slot here and the power connector). Regardless, this would fit in any (Baby)AT case. Conversely, these boards were frequently used in very small proprietary cases, usually with a riser. To fit in there a board would need to be max same size as this, with holes in same places (not usually a problem as baby AT standard) and whatever slot is used by the riser in the same place too.

So any AT case would be fine for the board. 1-1 replacement of board should be fairly easy, most late 386SX boards were similar to these. Upgrade would be a challenge. I have a similar 486SLC, but boards with 32b external bus are rare at this form factor. Only exception are a couple of late Vtech/PCPartner boards like the VIB878DS (So7, Via MVP3-based) with AGP that can fit a K6-2 in the same form factor. That said, not much chance of fitting into the same case - that ISA riser won't fit in an AGP slot and even if the riser were at the end of the board, you still have the issue of heat production of a K6-2 vs 386SX - it would probably melt in a tiny case like some 386SX.

Thanks for the information.
This case seems quite small Re: where can I find a baby AT case

anton23 wrote on 2024-04-02, 19:23:

[...]

Both. Although most of the boards I saw in that size are 386SX and I'd like either DX or 486.

Like I said, 32b I/O is unusual in this form factor. 486SLC (i.e. souped-up 386SX with internal cache) is about the best that's fairly commonly available and won't roast your small system.

I'm looking for a small x86 (preferably like 386 or 486). I've seen SBCs but they seem quite expensive, and usually require a backplane.

Backplane SBC systems are a completely different kettle of fish. They are generally a lot bigger, having an SBC for easy interchangeability rather than small form factor. I have two PICMG backplanes that are full baby AT size, with the expectation of multiple full-length cards (i.e. well over twice the length of an ISA slot). I was referring more to using this little motherboard as 'backplane', with a tiny 1, 2 or 3 slot riser in one of the ISA slots. I have a system like that at work (to play Arkanoid II in lunch breaks), but don't have any pics of its innards.

[...]

Thanks for the information.
This case seems quite small Re: where can I find a baby AT case

That is a regular (albeit very compact and cramped) babyAT case that will fit a board twice as long as the one you posted. It will fit this little one perfecty too.

https://www.dosdays.co.uk/topics/Manufacturers/sarc.php

not the exact match but slight variation of what you got. And it might be UMC chipset (see Identifying PCChips 386 era chipsets)

dionb wrote on 2024-04-02, 21:54:

Like I said, 32b I/O is unusual in this form factor. 486SLC (i.e. souped-up 386SX with internal cache) is about the best that's fairly commonly available and won't roast your small system.

I see, thanks. What would be the smallest 386 or 486 with 32bit bus ? I used to have a 486 with VESA VLB for video, but I had to trade it in the 90s when I needed more power. I remember it was a small case, unfortunately I don't have any pictures of it.

Backplane SBC systems are a completely different kettle of fish. They are generally a lot bigger, having an SBC for easy interchangeability rather than small form factor. I have two PICMG backplanes that are full baby AT size, with the expectation of multiple full-length cards (i.e. well over twice the length of an ISA slot). I was referring more to using this little motherboard as 'backplane', with a tiny 1, 2 or 3 slot riser in one of the ISA slots. I have a system like that at work (to play Arkanoid II in lunch breaks), but don't have any pics of its innards.

Nice workplace with retrogaming for lunch!

I think I underestimated the need for the ISA cards when I saw this little board.

That is a regular (albeit very compact and cramped) babyAT case that will fit a board twice as long as the one you posted. It will fit this little one perfecty too.

Now I have to find a cheap one

MyJules wrote on 2024-04-02, 21:55:

https://www.dosdays.co.uk/topics/Manufacturers/sarc.php

not the exact match but slight variation of what you got. And it might be UMC chipset (see Identifying PCChips 386 era chipsets)

Thanks! Great website by the way!

anton23 wrote on 2024-04-04, 13:12:

dionb wrote on 2024-04-02, 21:54:

Like I said, 32b I/O is unusual in this form factor. 486SLC (i.e. souped-up 386SX with internal cache) is about the best that's fairly commonly available and won't roast your small system.

I see, thanks. What would be the smallest 386 or 486 with 32bit bus ? I used to have a 486 with VESA VLB for video, but I had to trade it in the 90s when I needed more power. I remember it was a small case, unfortunately I don't have any pictures of it.

Ah, sorry for the confusion. I'm not referring to VLB (or EISA or PCI) but rather the 32b memory bus of 386DX or 486. Even if you only have ISA expansion slots, a board with 32b memory bus is much more complex in terms of traces than a board with the 16b memory bus of the 386SX, and therefore usually bigger. That's why such tiny boards are rarer with 386DX/486. How on earth Vtech/PCPartner managed a 64b memory bus, ISA, PCI *and* AGP on the same footprint is something of a miracle.

(on an aside, 386SX boards with VLB also exist; VLB spec defines the option of 16b transfers instead of 32b, in fact a lot of cards only use the 16b transfers so the only benefit vs ISA is the much faster clock)

Nice workplace with retrogaming for lunch!

Well, the workplace tolerates it, we nerds built it for our own fun 😉

I think I underestimated the need for the ISA cards when I saw this little board.

In a really small system they will be quite a challenge.

You need:
- I/O controller (HDD, FDD etc)
- VGA

Very nice to have:
- sound

My tiny system has two ISA slots, one takes half-length cards, the other only does 8b ISA with 1/4 length, so at first I only had VGA and I/O. Then I found a combo VGA+I/O card, which let me add a sound card (Aztech Sound Galaxy BX II) in the more limited slot.

Here's a pic:

Note that that's a 12" monitor, the system is really tiny.

[...]

Now I have to find a cheap one

Sometimes the biggest challenge.

In my head I call them BabyBaby-AT but not sure they had an official name. There's about 10 brands of one of those that are all basically the same board, with an AMD386 on.. and half a dozen different designs on that footprint. So there are tons of 386 ones around, then a few of those that got the cyrix 386/486 chips. Then there's a design the same size with 486SX on, and few 486 variants. Rarer than the 386es... then fastest I've seen in that footprint, one with an AMD 5x86 DX5 plcc on the board... which I think we've only ever seen one of posted on Vogons, so that's gotta be a bit of a unicorn.