"Z.I.F Local Bus" Motherboard..........WTF is it?

[videobruce 0]

No, that's not a typpo, a friend has a computer dated 11/94 that lists a Z.I.F. local bus for the Motherboard.

It goes on to describe it as "allowing you to upgrade your system in the future as oppose to replacing it".

 

It lists a 66MHz 486DX2, 8MB of RAM, a 450MB HDD, 1MB of VL/VESA for Video RAM and Windows 3.1 & DOS 6.21; a really hot system w/ monitor and 14.4 baud modem for only $1900!

 

The only think I can think would be one of those LPX MB's with the separate connector board that the MB and the add on cards all plug into.

 

Anyone ever hear of this term?? I know today that ZIF is a CPU socket, but this is 1994 I'm talking about here.

[adamvjackson 0]

I would wager that it referred to the CPU socket. If I recall correctly, some of the pre-ZIF systems actually had the CPU soldered to the board. But it's been awhile, and my memory is not everything it used to be.,

[mezron 0]

Quote:

I would wager that it referred to the CPU socket. If I recall correctly, some of the pre-ZIF systems actually had the CPU soldered to the board. But it's been awhile, and my memory is not everything it used to be.,

That was waaaayyy back when the cpu's were soldered (before my time with computers anyway, my first was a 286). During the 286-486 era pre zif socket I forget the name of the socket that the cpu went in to but you had to give it a good push to get it in. It didn't have the lever on the side to release it, and you had to be really careful to take the cpu out otherwise you'd break or bend the cpu pins. Kind of like taking the lid off a paint can but with a lighter touch

Jim

[adamvjackson 0]

Quote:

No, that's not a typpo, a friend has a computer dated 11/94 that lists a Z.I.F. local bus for the Motherboard.
It goes on to describe it as "allowing you to upgrade your system in the future as oppose to replacing it".

Now, for the local bus part: I suspect that was referring to VESA-local bus, which would fit in the same timeframe as the ZIF socket becoming mainstream.

However... What you have to do now, is open the case up, and post some pictures!

[videobruce 0]

I haven't even seen the box. I did think there might be a connection to that VESA local bus and this, but I figured it might be 2 different things.

[adamvjackson 0]

VESA was only used for graphics, as I remember.

[videobruce 0]

Dito............

[mezron 0]

Quote:

VESA was only used for graphics, as I remember.

I think thats really all it was ever used for, but it wasn't limited by design to just graphics. It was kind of a competing bus to pci and eisa (32 bit isa). pci won out. I'm not exactly sure but I think it was due to pci being more plug and play by design. A lot of things like diagnostic software had a hard time with vesa, you sometimes had to tell the software there was a vesa bus there for it to find any devices on it.

Jim

[adamvjackson 0]

Technically, VESA ran at 40MHz and PCI at 33MHz. So, at the time, VLB was superior. But again, VHS vs BETA.

[mezron 0]

Quote:

Technically, VESA ran at 40MHz and PCI at 33MHz. So, at the time, VLB was superior. But again, VHS vs BETA.

Was that just on the 486 DX2 80 or was that on all systems? 40Mhz is kind of an oddball number even during that time period ;( . How fast did it run on 25Mhz multiplied systems like the DX4 100? I do remember it being something of a Beta vs VHS thing also though.

Jim

[Admiral LSD 0]

Quote:

Technically, VESA ran at 40MHz and PCI at 33MHz. So, at the time, VLB was superior. But again, VHS vs BETA.

VESA ran at whatever speed the 486 host bus was running at, anywhere from 16Mhz right up to 50Mhz, due to the fact that it was essentially the 486 host bus wired into a slot connector. This made it cheap and easy to implement on 486 systems but difficult on any other. It wasn't really stable above 33-40Mhz either (as I found out when I installed a VLB disk controller on a 486DX-50 system) due to timing problems in the host bus which made PCI's detachment from the host bus a much better idea in the long run.

[Champion_R 0]

Quote:

Technically, VESA ran at 40MHz and PCI at 33MHz. So, at the time, VLB was superior. But again, VHS vs BETA.

PCI does all sorts of other stuff like bus mastering, etc that would make it superior.

[FrankE 0]

Hi,

 

first of all VESA local bus wasn't graphics only. (I think you meant VESA graphics BIOSes). VLB boards incorpporated up to three VESA slots even that allowed bus mastering. Even VLB-IDE controllers were available.

My DX/2-66 had a Side Jr. plus Multi-I/O-Controller card. It was even capable of PIO4 and ECP/EPP (bidirectional communications on printer ports) and had highspeed serial ports with 16550 UARTs. - Amazing back then.

 

You could have VLB running synchronous with the FSB. which was great with 486ers, especially with the later AMD ones (DX-40, DX/2-80, DX/4-120).

 

The main disadvantage VLB had was:

The standard was immature. many motherboards had electrical and H/F issues. All three slots were only to be used with 25 MHz FSB. According to the specification higher FSBs left one or two slots unusable. You could have luck and an additional card would work even at a higher clock.

Otherwise you still had the chance to use the ISA portion of the slot (a VESA slot was a combination of a local bus and a 16-bit ISA part).

 

With 33MHz PCI solutions were asynchronous to the FSB resulting in waitstates but a higher stability with up to four/five slots usable in all configurations. Thats why Intel promoted it as the only solution for their Pentiums.

 

Any questions left ?