Quadra 950 - Power Tower

[trag]

I'm curious about the "fast" SCSI bus on 950, 840AV and x100 series NuBus Architecture PowerMacs and its relationship to a full on Fast/Narrow SCS-2 implementation. What's the SCSI throughput of Apple's boards?

Only the X100 has Fast SCSI II (10 MB/s) and then only on the second, internal-only bus on the 8100 and 9150.   The Q950 and 840AV just have SCSI II (5 MB/s), unless the add in card for the 950 is Fast.  But I'm pretty sure it's based on the 53C96 which is just boring SCSI-II with no Fast.  You need a 53CF96 (note the central 'F') to get Fast SCSI.

The internal-only SCSI bus on the 8100 and 9150 actually uses a 53CF96 chip.    On later machines, they switched to a "custom" Apple MESH chip, which is in exactly the same package as the 53CF96 and probably is just a licensed 53CF96, as the IP for that chip was widely licensed.

 

[CC_333]

It's been discussed before, but I wonder if that chip would be more-or-less interchangeable with its non-"F" counterpart?

A vague memory says maybe, with a lot of work....

c

 

[Trash80toHP_Mini]

Thanks trag! Might the 53CF96 be a drop in rework replacement for the 53C96 on a 7100 board that might just work or is there a lot of othe junk on that second bus?

EveryMac lists my 81/110 as Fast SCSI, I'll have to check the boards? Doesn't matter, I've got the JackHammer/Studio Array, but I'm curious about what they did.

 

[IIfx]

So I haven't got a chance to benchmark the SCSI2SD 5.1/Q950 SCSI Bus yet in anything aside from Norton Utilities. It scored in the high 80's if I remember right, above most lower end 030 Macs but well below the Quadras, so the SCSI2SD is holding it back. Possibly due to crippled random write speeds.

OWC RAM order still hasn't shipped because PRAM batteries are on back order. Don't know how long I need to wait until they ship the RAM at least. The 3D printed CD-ROM Bezel I ordered from Shapeways should be here soon, thank you 360alaska for designing the bezels! A tip is heading your way once I get my next paycheck.

 

[Trash80toHP_Mini]

I haven't put my toes near the SCSI2SD waters for fear of being sucked down a monetary whirlpool. If and when it will almost certainly be the V6 for the ATTO Fast SCSI2 Card in the pet IIfx. That one gets the pampering. []

 

[trag]

Thanks trag! Might the 53CF96 be a drop in rework replacement for the 53C96 on a 7100 board that might just work or is there a lot of othe junk on that second bus?

EveryMac lists my 81/110 as Fast SCSI, I'll have to check the boards? Doesn't matter, I've got the JackHammer/Studio Array, but I'm curious about what they did.

The 7100 only has the single slow bus.  Only the 8100 and 9150 had two SCSI busses.

On the entire X100 family, the boring SCSI is in the AMD AM79K950 (? think the first two digits might be wrong but its the only big AMD chip) CURIO chip.   There's no replacing the SCSI chip because it's embedded in taht much larger chip that does serial and ethernet as well.   The 8100 and 9150 add a discrete 53CF96 for the separate Fast SCSI bus.

This model is also used on teh X500/X600 family, except, every member of that family has the second Fast bus, but not the 7200...   EveryMac must be referring to just the extra internal-only bus, or it's wrong.

Apple started using CURIO (custom chip from AMD encompassing serial, SCSI, enet) in the Quadra AVs and continued through the end of the x600 family.  Didn't change until Beige came out.

There was a lot of confusion when SCSI II was codified.   The SCSI II standard is the one that introduced Fast and Fast & Wide SCSI, and lots of folks started calling things that newly met the SCSI II standard, "Fast SCSI" even though they just met the 5 MB/s SCSI II standard.  They did not implement the optional 10 MB/s protocol.   True, SCSI II was faster than what came before, but not all SCSI II is Fast SCSI II.  

The 81/110 is just like the 8100.  Exactly the same down to the tiny SM resistors.  The only difference is the video out connector.

 

[Trash80toHP_Mini]

Thanks again, figured as much. That DA-15 connector would be a huge convenience as compared to Apple's monstrosity. But I'll likely never use it. I've got enough pixels pumping out via the GX 1600 and 4MB HPV connectors..

This thread has me wanting to pull my own 950 out, but I'm in the middle of trying to put stuff away. :

 

[ArmorAlley]

What's the screen-draw performance like on a 1600x1200 monitor? I tried it on my IIfx with a Thunder/24 and it was *slow*.

A PM 8100/110 does have a faster NuBus bus and a faster processor though.

 

[Trash80toHP_Mini]

Can't really say. I've never really tested it for redraw speed, used it for gaming or Illustrator production IRL, so I don't know. The Radius 81/110 is a neglected toy I'm slowly setting up in their ultra spec. System 100 config but for VideoVision Studio VidCap which uses its own, dedicated display.

My 1600x1200 experience started when I hacked the 6360'G3 to house a full length VidCard that's pretty much a Thunder IV GX 1600 adapted to the much faster PCI interface after snagging a PrecisionView 21" to replace the aging IntelliColor 20" Radius monitor. Just after that I "collected" the Radius 81/110 of my dreams after PCI Macs had relegated it and its X100 series and Clone kin to obsolescence. Not sure, but that was probably my first conquest, before that I was a hoarder of everything I'd ever used IRL. That was a good twenty years to collecting the kit I've yet to set up, but it's all safely stored away in that big metal box.

The Q950 I finally dropped off to IIfx was either the Goodwill find or given to me for helping someone out at the storage facility in 2004 along with a board rotting 840AV I've only ever used as a coffee table support. It's very strange how we get into the hobby.

As an aside, it took me a few years to get around to playing with the Rocked/SCSI 2 Daughter card you sent me in exchange for your Little Red Pixel Rocket and that spare mohonking box sitting neglected. Very happy here and most happy everything is as was when I secreted the front panel plastics within the drive cubic of that beast. The delay was all good, glad that ploy was never tested in shipping. []

 

[IIfx]

OWC finally shipped out the RAM. Turns out NewerTech no longer supplies them with 3.6v 1/2 AA PRAM batteries so they had to rebuild my order without the battery. I went ahead and ordered some PRAM batteries off of ebay, the blue PxCell ones. I've had good luck with these in the past.

The Q950 was a bit grumpy installing the new RAM. Cleaning the SIMM slots with contact cleaner cleared the death chimes.

Within a few paychecks I will be bumping the system to 256mb RAM. I have a feeling that OWC's supply of new 30 pin SIMM's will dry up.