SCSI 2 SD Version 6 Card 2020 Rev C working !

Started by Rob Blessin Black Hole, April 30, 2021, 02:35:15 AM

Previous topic - Next topic

Rob Blessin Black Hole

Hello NeXT Community: I took the plunge and have the SCSI2Sd Version 6 card working 2020 Rev C , the ealier vesion were always problematic ..... this is in process so I'm not sure of stability.

I also just ordered some exterme pro 16Gb SD Cards 170Mbs which ought to be interesting to check against the 95Mbs cards .

I prefer the Version 5.2 Cards becaue of proven stability but the version 6 cards provide direct access to the card , I'm tinkering .....    Best Regards Rob Blessin
Rob Blessin President computerpowwow ebay  [email protected]
303-741-9998 Serving the NeXT Community  since 2/9/93


Curious to see if you can benchmark a difference. I think I read that the bus to the SDCard interface maxed out at 20/Mbs. But I could be wrong. :)



I'm not sure how much benefit there would be for faster cards. The NCR 53C90 and 53C90A
used in the next are SCSI-1. The 53C90 was PIO only, without DMA. The later 53C90A rectified this and added DMA.

So with SCSI-1 the absolute maximum speed we can see is 5MByte/sec. But with a 53C90 (PIO) I doubt we'd get that. 53C90A (DMA), probably. But you're still capped at 5MByte, etc.

I wonder if there are any faster drop in replacements for the NCR chip? Fast-20 SCSI can do 20mbyte a sec which would be lovely.


Just be clear, I'm not against testing. Absolutely you should benchmark everything you can.
Then change one variable, and test everything again.


Looking forward on the result and stability of v6 as well! :)
NeXTcube 030 1990 with 040 upgrade - no longer
NeXTstation Color Turbo - Current.


TIL the 53C90A in my NextStation Turbo is a SCSI-1.

I thought it was SCSI-2, which was how I had enabled that on my SCSI2SD v5.

I've never been that happy with the performance, mostly latency, even with a fast Samsung SD Card.
I was playing around with it today and found I could get between 1MB and 3MB out of it with most of the options now disabled. Feels better (latency) so it will do me.

I only enable Parity and DisableGlitchFilter.
Everything else is off.
:O2: r12 400 mapleleaf :Indigo2IMP: r10 195 IRIS :SlabMonoTurbo: NeXT
New Zealand