Help identifying two internal ST expansions (NEC v30)

[gamer-stu]

Hi all, I recently acquired a local 1040STF system and opened it up to give it a clean.

 

It has two expansions, one of which I'd like help identifying. 

 

The easy one is clearly a RAM expansion, I'm guessing an additional 1MB.

 

I have no idea what the other one is. It includes an nec d70116c-8 v30, which I thought was in the x86 family. Thoughts on what it's doing in my ST? Some sort of PC emulation?

 

 

[gamer-stu]

I think I found it. It is PC-Speed by Sack Electronic. I have the system disks, but need to create a DOS disk to try it out.

[TZJB]

13 hours ago, gamer-stu said:

Hi all, I recently acquired a local 1040STF system and opened it up to give it a clean.

 

It has two expansions, one of which I'd like help identifying. 

 

The easy one is clearly a RAM expansion, I'm guessing an additional 1MB.

 

 

The SIMM memory expansion provides an additional 2 MB. Both SIMM have 1 Mb 511001A chips on board.

 

It looks like a Frontier/Marpet Xtra-RAM Deluxe with the additional memory adding a 2MB bank 1, with bank 0 being the existing onboard RAM of 500 kB.

 

As you have a 1040STF model, bank 1 has replaced the second onboard 500 kB bank to give 2.5 MB in total. If you wish to add two more 1 MB SIMMs to the Xtra-RAM deluxe, and disable the onboard RAM bank 0, you will have the full 4MB.

 

XtraRamDeluxe_InstallationManual.pdf

[gamer-stu]

Many thanks TZJB!

[leech]

13 hours ago, TZJB said:

 

The SIMM memory expansion provides an additional 2 MB. Both SIMM have 1 Mb 511001A chips on board.

 

It looks like a Frontier/Marpet Xtra-RAM Deluxe with the additional memory adding a 2MB bank 1, with bank 0 being the existing onboard RAM of 500 kB.

 

As you have a 1040STF model, bank 1 has replaced the second onboard 500 kB bank to give 2.5 MB in total. If you wish to add two more 1 MB SIMMs to the Xtra-RAM deluxe, and disable the onboard RAM bank 0, you will have the full 4MB.

 

XtraRamDeluxe_InstallationManual.pdf 2.71 MB · 3 downloads

That's a really odd setup, isn't it?  Generally, I'd think with that RAM upgrade, you'd just disable the motherboard 1mb, and put in the four SIMMS.

[Zogging Hell]

8 hours ago, leech said:

That's a really odd setup, isn't it?  Generally, I'd think with that RAM upgrade, you'd just disable the motherboard 1mb, and put in the four SIMMS.

It's what I did when I first got a Marpet upgrade back in the 90s. This way there are no modifications beyond the base install to do (no cutting) so for people are scared of damaging something (like I was at the time) it was the easy way to go. Memory was also pretty expensive back then as well so a bit of saving. Not to mention that 2.5mb is slightly more compatible than 4mb in some circumstances.

[TZJB]

18 hours ago, leech said:

That's a really odd setup, isn't it?  Generally, I'd think with that RAM upgrade, you'd just disable the motherboard 1mb, and put in the four SIMMS.

 

Generally you would be correct, however historically it was not economical or necessary to go straight to 4 MB of RAM.

 

The original Frontier Software Xtra-RAM provided for 0.5MB or 2 MB, using discrete DRAM chips for RAM bank 1. The 16 DRAM chips were very relatively expensive at the time.

 

Xtra-RAM.pdf

 

The Xtra-RAM Deluxe upgrade provided the choice of a 0.5MB, 2 MB or 4 MB depending on the combination of two or four 30 pin SIMM.

 

SIMM memory also became very expensive due to a shortage, so much so that it was regularly being stolen from business PCs and routers in overnight raids.

 

Therefore a 2.5 MB machine was an economical decision at the time and nominally provided enough RAM to run a hard drive and support the programs loaded from it.

[leech]

On 8/29/2024 at 4:14 AM, TZJB said:

 

Generally you would be correct, however historically it was not economical or necessary to go straight to 4 MB of RAM.

 

The original Frontier Software Xtra-RAM provided for 0.5MB or 2 MB, using discrete DRAM chips for RAM bank 1. The 16 DRAM chips were very relatively expensive at the time.

 

Xtra-RAM.pdf 3.15 MB · 2 downloads

 

The Xtra-RAM Deluxe upgrade provided the choice of a 0.5MB, 2 MB or 4 MB depending on the combination of two or four 30 pin SIMM.

 

SIMM memory also became very expensive due to a shortage, so much so that it was regularly being stolen from business PCs and routers in overnight raids.

 

Therefore a 2.5 MB machine was an economical decision at the time and nominally provided enough RAM to run a hard drive and support the programs loaded from it.

Yeah, my thought was more about 'these days' rather than historically.  But then, I'm an upgrade goblin who will buy a system just to upgrade it with modern stuff... for example, bought a Coleco Adam because a Fujinet was made for it.

[TZJB]

13 hours ago, leech said:

Yeah, my thought was more about 'these days' rather than historically.  But then, I'm an upgrade goblin who will buy a system just to upgrade it with modern stuff... for example, bought a Coleco Adam because a Fujinet was made for it.

 

I agree. These days, there is no reason not upgrade an Atari ST to the full 4 MB of RAM, especially if you have an STE model or a Marpet Xtra-RAM already fitted that takes SIMM memory modules, as memory is now relatively cheap.

 

However upgrading the memory in a standard Atari ST or MegaST is a little more challenging for a reliable memory upgrade, unless you are good at soldering in my opinion.

 

For instance I have a Marpet Xtra-RAM in one of my Atari ST machines, but it has been soldered in as the MMU is soldered to the board and not socketed. It makes the memory upgrade much more reliable though.

 

I also have a Fujinet - for my Atari 8 bit computers. Unfortunately I am unfamiliar with a Coleco Adam or anything Coleco for that matter. It was never released in GB.