Getting the most out of A3000's SCSI

[AmigaHope]

By the way I highly recommend you read my thread here:

http://eab.abime.net/showthread.php?t=101222

The A3000 SCSI controller is basically the best-case scenario for system-level write caching (fast memory bus, fast CPU, extremely slow I/O pipe, but DMA-driven to protect the CPU). Multitasking improves immensely with caching software if you're using the A3000 SCSI controller.

[trixster]

Testing the A3000 again now - A3640/060 in sync mode with an Acard 7720UW, but this time with AMD scsi chip and DMAC-04. It’s now 3.3MB/s

[DarrenHD]

Originally Posted by trixster

Testing the A3000 again now - A3640/060 in sync mode with an Acard 7720UW, but this time with AMD scsi chip and DMAC-04. It’s now 3.3MB/s

That's I think the maximum real world you will get. I get the same with a 50-pin SCSI drive and also with my SCSI2SD V6. I am using SFS with 1024 buffers.

[trixster]

With the A3640 just as an 040, it's 3.43MB/s

[matt3k]

Originally Posted by Overmann

Yeah, I suspected that might be the case. Is an accelerator with onboard SCSI the best way to go with the A3000 then? Far outside of my pricerange, but just curious. How would the fastlane stack up? FastATA are not DMA I understand, so while fast they would tax the CPU?

Yes, an accelerator is the best way go for SCSI performance. The 3000 SCSI is still decent. Make sure to set you max transfer and mask up for ideal performance (Mask 07FFFFFFE Max FFFFFFFF), set buffers high (500), use PFS3, and use a disk caching program like FastCache. All of these will give the best performance you can squeeze out of SCSI.

Yes, IDE does tax the CPU and SCSI will not.

I suggest getting either a CF or SSD, they are really nice in the Amiga IMHO.

Numbers really don't mean much, since all the scsi test programs very wildly, so go with the best observations...

For example Scsibench claims I get 16,MPS because of fast cache, sysspeed claims 2.85 MPS for create/write and sysinfo is anywhere from 800k to 2.35mbs. So don't worry about specs, worry about results.

[eXeler0]

Howdy,
still have a genuine SCSI disk in my rarely used A3000, but now I got new ROMs and ordered 8MB zip ram.

So was thinking about the SCSI2SD that a lot of ppl seem to get for their A3000s.
Even saw an external version with the benefit of having the SD card easily accessible. However, seems transferspeeds are in the 2MB/s ballpark. Maybe not a huge deal for a 30+ years old computer…but..
Now to the actual question; is it better to just get the slightly more expensive FastATA 4000 MK-VII and strap on a standard IDE2CF adapter? (seems to deliver mush higher transfer speeds).
Any disadvantages? Issues with jumper settings for boot etc?

[Jope]

No DMA with the FastATA. Slower DMA SCSI might be nicer in some use cases than faster PIO IDE.

[eXeler0]

Originally Posted by Jope

No DMA with the FastATA. Slower DMA SCSI might be nicer in some use cases than faster PIO IDE.

You are right about DMA of course, but realistically, not something Id notice under limited use as opposed to some sort of production environment one probably had back in the day..
So factors like easy setup, physical accessibility also count. External SCSI2SD looks convenient but its sticking out on the back quite a bit so thats a thing too.

[Jope]

Yep, in reality I'm sure most of us are mainly single tasking our Amigas these days.

[alexh]

Discussed in another thread. The onboard SCSI is likely to stop working after you fit an A3660. Great if it still works but there is a good chance it won't. Just keep that in mind before spending any money.

[eXeler0]

Originally Posted by alexh

Discussed in another thread. The onboard SCSI is likely to stop working after you fit an A3660. Great if it still works but there is a good chance it won't. Just keep that in mind before spending any money.

Ok, so that's another argument in FastATA's favour, however after being real close to getting a 3660 at one time I decided against it mostly because I think its weird to have an accelerator without RAM. If the Warp 4060 ever comes out (and fits into an A3000 that might be a better upgrade )

[alexh]

The TF4060 is coming out very soon. Fits in the A3000. Onboard eIDE is faster than onboard SCSI. Not as fast as FastATA (why? Not sure).

https://www.exxoshost.co.uk/forum/vi...hp?f=75&t=5188

[eXeler0]

Originally Posted by alexh

The TF4060 is coming out very soon. Fits in the A3000. Onboard eIDE is faster than onboard SCSI. Not as fast as FastATA (why? Not sure).

https://www.exxoshost.co.uk/forum/vi...hp?f=75&t=5188

Holy crap, didn't know that was coming already, thanx for the tip @alexh

(Should probably get on the waiting list for 2 (so that the A4000 doesn't get jealous)
Just ordered 8MB ZIP RAM för $135 btw, oh well ;-)