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Where are all the SCSI2SD devices? Is this because of the chip shortage?

Trixter

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SD is slow

I will agree they are very slow. But I use them in old slow hardware anyway so the slowness is not a real problem.

My area of focus is early x86 systems (8086-80386), and I've found that CF/SD/flash -- while having a lower sustained transfer rate than spinning rust on some fast controllers -- are effectively faster than spinning drives because the IOPs are easily 3x or more. Obviously YMMV, but some applications like databases feel like they're running out of a ramdisk on flash storage, vs. being glacial on spinning drives. Same for environments that do a lot of random I/O, like Geoworks.
 

NeXT

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Oh I will absolutely not deny that a SCSI2SD will beat the pants off the SCSI-1 or even FastSCSI bus in a 486. I was referring to above that when I start seeing them in high-performance systems with bus adapters and UltraSCSI/U160 systems where you begin to notice it holding you back. Stuff where at this point it would be nice to see something converting SATA to hit even half the U160 spec but outside of ACARD there's nothing available yet.
 

njroadfan

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To be fair, systems capable of UltraSCSI and friends usually have readily available options for fast PATA or SATA. Even if the SD card is "slow", you are eliminating head seek time from the equation.
 

VERAULT

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I didnt know were were talking ultra scsi. I used to setup and moderate U320 Arrays. I thought we were talking SCSI 1 and 2. Modern-ish scsi is not what I think of when I think vintage computing.. although its getting up there in Age.. Man I love SCSI.
 

NeXT

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We were not originally. I just see SCSI2SD in machines that do have UltraSCSI because the new owners complain about how loud the original drives were and you can really tell when you are maxing out what the adapter can tolerate compared to inside a Mac SE, late 80's SGI or possibly even an 8600 on the slower bus.
 

VERAULT

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with that said I would not jnstall a scsi2sd on an ultra scsi bus.

Also im a bit removed from mainstream server drives. What kind of modern scsi drives if any are made? are they all sata? I worked with serial attached scsi for a while, SAS. I dont know if it the tech went anywhere however.
 

Eudimorphodon

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Even if the SD card is "slow", you are eliminating head seek time from the equation.

Yeah, I think this badly needs to be kept in perspective when we're talking about vintage applications. Every time I mention I'm a fan of those PATA to SD adapters I cringe knowing the odds are decent that SOMEBODY is going to take it as their cue to yet again jump into a random thread, hop on a soap box, and start slagging on and on how just simply UNACCEPTABLE low-end flash solutions are for ANYTHING and you have to be an ABSOLUTE MORON to think otherwise... Sigh.

It's positively comical when the subject of the discussion is something like an XTIDE adapter in a 5160-class machine; I mean, for crying out loud the original XT hard disks transferred data at only around 85K a second with IBM's default interleave and had access times in the 80-100ms ball park, and I can testify from using one back in the day: even that was fine. Just absolutely, perfectly fine. When your program binaries are measured in tens or small hundreds of kilobytes even that piddly data transfer rate was enough to get the job done, blew the doors off a floppy. And, of course, even if somehow you had the slowest SD card paired with worst XTIDE adapter ever made not only is your data transfer rate going to be two or three times faster, the access time is going to like 50 times as fast, and that's the thing that's going to really make a difference if you're running something "disk-intensive". (IE, doing more than just loading a binary and running it.) The SD card adapter in my XT-class machine benchmarks effectively the same as an EMS RAMdisk, for heck's sake, it literally goes as fast as the 8-bit ISA bus can go without externally pumped DMA, with 1.4ms access times. Grrrr...

And of course the same objection crops up all the time even if the combination being discussed is something like a Mac Plus and a SCSI2SD. Sorry, the only way to make a Mac Plus' SCSI go fast is fire the computer out of a cannon. SD performance isn't a problem here. Not ever. :p People regularly use the HD-20 emulation on devices like the FloppyEMU as full-time hard disks on those machines and don't really notice it's any slower despite using the floppy drive port. (And this sort of makes sense if you're running appropriate software; you're probably not loading more than a few dozen/hundred kilobytes at a time. Access time for the win, again.)

That said, I guess I will admit that better SCSI replacement solutions for faster computers (post-1995-ish?) are an... under-served area, considering that devices like a SCSI2SD do *technically* max out at raw data transfer rates that really high-end "early-mid-90's", SCSI hard disks could manage. (Vs. the late-90's-ish performance that PATA->SD solutions offer, plus the option of various PATA to SATA/M.2/mSATA/whatever converters which are also widely available and cheap.) But I can sort of understand why no mainstream manufacturer bothers with this stuff anymore; Ultra SCSI was, in the broad scheme of things, a fairly short-lived and high-end niche technology. The sort of applications it was used for don't favor the computer outlasting the drives in "real production" the way more humble applications do. (A dog slow SD adapter or DOM will do just fine, thank you, in that greasy PC that runs your 90's vintage machine tool or whatever.)
 
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glitch

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The shortage of actual SCSI2SD boards from Rabbit Hole Computing is literally my fault. We still haven't gotten our new pick-and-place machines operational, and Rabbit Hole Computing is waiting on us to get that done. In the meantime, ZuluSCSI.
 

njroadfan

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Yeah, I think this badly needs to be kept in perspective when we're talking about vintage applications. Every time I mention I'm a fan of those PATA to SD adapters I cringe knowing the odds are decent that SOMEBODY is going to take it as their cue to yet again jump into a random thread, hop on a soap box, and start slagging on and on how just simply UNACCEPTABLE low-end flash solutions are for ANYTHING and you have to be an ABSOLUTE MORON to think otherwise... Sigh.

The only exception I've found to this is the CFFA3000 card vs. the RamFAST SCSI card. The RamFAST card is noticeably faster even when running off a 25+ year old hard drive. I don't know what kind of overhead the CFFA3000 has, but clearly the DMA transfers and 256k onboard cache are giving the RamFAST a clear edge. The Apple II bus isn't even that fast!
 

Eudimorphodon

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The only exception I've found to this is the CFFA3000 card vs. the RamFAST SCSI card. The RamFAST card is noticeably faster even when running off a 25+ year old hard drive. I don't know what kind of overhead the CFFA3000 has, but clearly the DMA transfers and 256k onboard cache are giving the RamFAST a clear edge. The Apple II bus isn't even that fast!

This is probably the exception that proves the rule, especially if you're using an Apple IIgs. It's a kind of unique machine in terms of how it has a lot of RAM and a fat OS but it's all stuck behind pathetically small pipes. (CPU has to slow down to 1Mhz, and interrupts are hardly a thing on the platform.) Anything that gets you away from polled I/O is going to be a win. But this isn't the flash's fault, I'm sure the RamFast card would run perfectly well with a SCSI2SD or the like on it.
 

VERAULT

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So I started using the Zulu SCSI board. I am using on it on Macintosh Color classic with system 7.5.5.

Unfortunately I have gotten some crashes, which lead to data corruption on the bootable partition. I have been working at getting a SCSI CDROM which has the capability to read CDRW discs and in testing a few times the system locked. After which point the bootable partition would not boot and I would need to run disk firstaid from FLOPPY or the bootable Apple LEGACY OS CD.

This is pretty much the same issues I was getting with blue SCSI. Obviously my experience is my own as is the testing I have done but I just thought I would pass on my experience with ZULU SCSI so far.
 

aperezbios

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So I started using the Zulu SCSI board. I am using on it on Macintosh Color classic with system 7.5.5.

Unfortunately I have gotten some crashes, which lead to data corruption on the bootable partition. I have been working at getting a SCSI CDROM which has the capability to read CDRW discs and in testing a few times the system locked. After which point the bootable partition would not boot and I would need to run disk firstaid from FLOPPY or the bootable Apple LEGACY OS CD.

This is pretty much the same issues I was getting with blue SCSI. Obviously my experience is my own as is the testing I have done but I just thought I would pass on my experience with ZULU SCSI so far.
Hi, there, have you reported any of those issues to Rabbit Hole Comuting? Which firmware version are are you using? Don't be so quick to dismiss a product that's young, when it was designed to be firmware-upgradable. Engage with the manufacturer!
 

VERAULT

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Hi, there, have you reported any of those issues to Rabbit Hole Comuting? Which firmware version are are you using? Don't be so quick to dismiss a product that's young, when it was designed to be firmware-upgradable. Engage with the manufacturer!
Im not dismissing the product. I know its new on the market. Its built extremely well. Its just not at a level of maturity I had hoped for.
 

dankcomputing

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I've tried the ZuluSCSI on several Amiga 2000 systems and a couple of SE/30s. So far the only annoyances have been coming up with a properly-sized hard drive image to use the space on the card efficiently. I even made use of the multi-drive feature when I tried it on the SE/30.

The biggest thing it's work in progress nature has affected is the documentation, that's not all in one place yet.
 
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