What is this card?

[kreats]

Saw this on ebay - looks a bit expensive, but I'm interested in what it does. The seller calls it a scsi card, but I see a motorola chip and a ram expansion.

I suppose it could be a caching scsi controller, but I couldn't find any info about it online.

Here's the link:

http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=330217702774&category=4601

Any ideas?

 

[Unknown_K]

It is an old rare Daystar caching SCSI card. I would love one of those (actually the PDS version for the IIfx is the one I realy want), but not at that price.

Daystar SCSI Powercard is the correct name for it. I have a scan of the advertisement for it. Up to 16MB RAM, DMA controller, up to 5MB/sec, dedicated 68000 CPU.

 

[kreats]

Nice! Yeap far too expensive.

Wonder how it stacks up to the more modern nubus scsi cards (jackhammer, atto IV). It looks like it's from an earlier generation than these. The onboard processor + caching might be of more benefit in underpowered mac II style macs.

I remember looking into caching controllers for my (486) dos box, but the consensus from my research seemed to be that so long as you were using a reasonably modern drive (that could deliver data as fast as the bus can operate) it was of minimal/no benefit. Also, you generally only saw caching in ISA controllers & nubus is more like PCI than ISA in terms of speed.

Most modern drives have a ~8MB/16MB cache onboard anyway I guess. Doubling up in this way probably wouldn't yield much benefit.

It'd be one I'd be interested in seeing benchmarks for across a range of macs vs other available cards.

 

[Unknown_K]

I have plenty of VLB caching controllers, they speed the system up because the built in CPU (286-20) takes the load off the CPU. The cache does help out the transfer speed as well. VLB machines have limitations on how big of a HD they can use, and drives that are usable are not that fast (IDE).

The 5MB/sec must be SCSI 1, the later Jackhammers and SEIV will smoke that card. Still its a nice card for an old Mac II, IIx, IIcx.

 

[kreats]

In low speed computers I'd imagine they'd be worthwhile. A 286 had a VLB slot?? Thought VLB was mainly a 486 thing.

Just doing some reading up on the data cannon/RavenPRO PDS card.. mm that sounds like the SCSI card I want. Wonder how that compares to RAID from 2x ATTO IV cards.

 

[Unknown_K]

The VLB machines I use are 486 class (there are some rare 386/486 hybrids with VLB but they suck), the caching controller has a Harris 286-20 chip on it to offload the real cpu of the task of moving data around.

I have a RavenPro PDS (040 PDS slot) here somewhere, they should be the fastest 68K Mac SCSI card made. One SEIV will saturate the Nubus bus with a couple good drives, with PDS you can get a bit more speed.

 

[Anonymous Freak]

And caching cards are still available today. The RAID cards for the Mac Pro and Xserve have 256 MB of RAM onboard for caching.

Caching cards have never been for 'desktop' computers, and have been a bit of overkill for low-end 'workstation' computers. But they have been common for 'servers' for a very long time.

 

[kreats]

oh ok I thought the 286 cpu was built into the motherboard not the caching controller. The modern caching controllers seem to be mainly for RAID cards btw.

I think benchmarks are the key to solving the mystery of if they are worthwhile or not.

I'd like my q950 to be the best it can be - but when you are choosing between a powerpro with 128mb 72-pin ram expansion (usable in 68k mode) or a scsi pds card, you'd want to be sure the benefit is there.

 

[LCGuy]

I'd go with the PowerPro, 72 pin SIMMs are *much* easier to find than 30 pinners, and IIRC the 950 already has a fast SCSI bus.

 

[kreats]

well the q950 is already maxed with 256mb, afaik the 72pin ram is used in preference to the 30 pin, so some improvement might come there.

The 950 has a fast scsi interface, but not a wide one - but yeah it's onboard so wouldn't have to go through a slow bus. Really have to do benchmarks IMO.

 

[trag]

well the q950 is already maxed with 256mb, afaik the 72pin ram is used in preference to the 30 pin, so some improvement might come there.
The 950 has a fast scsi interface, but not a wide one - but yeah it's onboard so wouldn't have to go through a slow bus. Really have to do benchmarks IMO.

I would double check that. I"m pretty sure that the Q900/950 uses the NCR53C96 SCSI controller which is not fast. It is a vanilla 5 MB/s controller. The NCR53CF96 is the Fast SCSI controller typically found in the later PM8100 which does have a Fast SCSI controller capable of 10 MB/s theoretical. As far as I know, none of the Quadras have a Fast SCSI controller built in.

Apple did not like Fast SCSI because it shortened allowable cable lengths and caused support headaches for them. This is why you will not find a single Apple model with an external SCSI port rated for speeds faster than 5 MB/s. They even went so far as to block off external connectors on faster add-on optional SCSI cards in later models.

Interestingly, the NCR53CF96 Fast SCSI Controller is in exactly the same package as the later Apple custom MESH controller found in the early PCI Power Macs. I wonder if they're pin compatible.

 

[kreats]

right you are - oops!