Blizzard SCSI module Vs Elbox FastATA MKIII

[coze]

I need suggessions for the route I'll take for my A1200 setup. I have a nice blizzard 30 MKIV in my mig. And I recently got a FastATA board. But I'm also about to buy a scsi module for my miggy. Which one should I go ? I didn't install the FastATA yet, so I can re-sell it as new if I go blizzard route. Actually, I'ld like something tidy and sticking to the original desktop case, so is FastATA a better option ? Is it possible to use a 2.5 scsi hdd inside the original case ? But I'm also little bit scared about the Elbox drivers after all the scary tales. What would you recommend ?

[keropi]

the blizzard scsi module uses DMA for transfers, thus it only takes very little cpu time. the fastata takes cpu time to transfer data.
fastata on a bppc 060/60mhz gave me ~5.5MB/sec ... never tried 1200 scsi though, but DMA transfer alone is a HUGE advantage.

[Secret Vampire]

I agree with Keropi on the SCSI front, it's the better way to go, you're unlikely to see the best performance of the fastATA with an 030, plus, the Blizzard SCSI module gives you an extra simm slot for more memory.

As far as fitting an internal drive, the blizzard does not appear to have a normal 50 pin header, just a 26 pin one for connecting to an external port, but, making an adapter to 50 pin would not be impossible. Drive wise, you should probably forget fitting a 2.5" SCSI, the common ones go up to about 300MB, roughly corresponding with the time when Apple switched to IDE in its laptops. Larger ones exist, but are very uncommon, and in some cases are just an IDE drive with a converter (which is near impossible to obtain separately) attached to the bottom, and then even if you did find one, you'd still need to find a suitable cable to connect it with.
Far better to squeeze a 3.5" drive in there, it will fit, though you may need to remove the top shielding, and it will be faster than most 2.5" drives. Seagate made a somewhat slimmer than normal version of their Medalist pro, which should be an easier fit, though it depends on the size you want, mine is 2GB, they probably didn't make them all that much larger.

[alewis]

You probably wont see a huge performance advantage from a SCSI drive over an ATA IDE, simply because the SCSI interface is limited to 10mb/sec max bandwidth. And you'll be hard pressed to obtain that, given the overheads involved.

On a Warp Engine 040, with an 2gb HP SCSI-2 drive, I get 5.5mb/sec. Using an ultra160 9gb SCSI Seagate, I get about 8mb/sec. However, as keropi rightly states, DMA does give a CPU advantage which is useful when multitasking.

In comparison, the same drive on a Cyberstorm060 UW-SCSI interface delivers 28mb/sec. Put into perspective, thats an ultra-wide (40MB/sec) interface with an u160 drive. The drive is probably operating at max, leaving around 10mb bandwidth on the bus.

PIO interfaces/drives have an advantage in that the faster the CPU, the fatser the transfers, to a point (the max bandwidth of the the controller, less overhead), which Secret Vampire highlights. Basically, although a FastATA interface might offer up to 16mb/sec in PIO mode 4, that requires a fast processor.

As for drives, well, I dont recall a 2.5" SCSI-2 drive. Seagate bought out a 2.5" SCSI range a couple of years ago, as I recall these are SCSI-3. You could use one - with the appropriate interface adaptor - as SCSI is backwards compatible, but it would be costly. And other than neatly fitting in the case, would not offer any performance advantage.

OTOH, 3.5" drives are hugely common. 9gb and 18gb U160 drives are practically being given away on ebay (and if not, I have loads). Sure, some case work required in the A1200, but thats only time and effort - and not money - being expended. Performance will be limited by the SCSI interface, but will max it out :-) and not overly load the CPU.

Just my tuppence worth.

[dambuster]

As your not using ide interface for anything, you could fit a CF to IDE adaptoe and use a CF card see this link http://eab.abime.net/showthread.php?t=25274
I use a 1 GB CF with an 030/40 and 4mb ram and the speed is great.

[Zetr0]

@dambuster

your loving that CF card arn't you *me too*

@coze

as an adjunct though, you can get an ide to scsi converter --> this inturn can goto ones ide -> cf adapter and there you have SCSI CF, with some darn impressive seek times ... also you can get 2.5" drives much cheaper on ide.

Alas there is a draw back to the ide - scsi conversion... the speed is limmited to the ide device as opposed to scsi channel, but since your only gonna get a small portion at best I doubt you would notice any performance hit.

a small bonus is that one can then have cheap IDE drives on a scsi managed chain thus (nice word that) free up CPU... kinda the best of both worlds really...

heres the sorta thing your looking for

love the ebay

the cost of these units can vairy widely, I have seen them sell under £10 and in the flip i have seen them sold arround £80, I have as yet to note any disernable difference....

[coze]

Thanks for all the advice, in the end I decided to switch my FastATA for a Blizzard module. The transfer rate is not a priority for me, I'ld like to keep my cpu load least I can, so that was the main reason. Another reason is I hated the idea of something sitting on my rom socket (I dunno why). If I can secure some income a willem eprom programmer is the next thing in my shopping list for some custom rom creation and iI thought t will probably require some intense rom swapping on the socket, and that's basicly the other reason. (ok, I think I need to use shorter sentences)