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SCSI to SD advice

smrieck511

Well-known member
hi, I'm restoring an SE/30 and am looking for any advice in terms of which manufacturer, termination etc. There seems to be several options. Thanks for any help.
 

cheesestraws

Well-known member
Main ones available now to my knowledge, each with different tradeoffs:
  • MacSD: extremely feature-rich, especially with features for CD-ROM gaming and easily getting stuff on and off that isn't in disc images. I mostly find myself using mine with early Power Macs, because that's where the features have been most useful to me. Competently designed and built in both hardware and software terms.

  • ZuluSCSI: Successor to scsi2sd. Significantly less featureful than MacSD but, in my unscientific experience, a bit more raw performance. Again, competently designed and built. A decent successor.

  • Scuzznet: A bit of an outlier; primarily a SCSI to Ethernet device but it will also do disk emulation. I've mostly used these in 000s to give them Ethernet.

  • RaSCSI/PiSCSI: The Mac fork of this was recently renamed to PiSCSI (IIRC). To me, this has always felt less like a drop-in drive replacement and more a 'SCSI device construction kit'. It's cool if you like fiddling with things, and it's almost infinitely configurable, but that means that as a "drop-in" device it's somewhat less successful. Swings, roundabouts.

  • BlueSCSI: It's cheap and you can build one at home, and beyond this it has almost nothing to recommend it. Dodgy hardware and there are strange timing glitches in the software. Termination isn't done properly. Usable in a 000 if you treat it as disposable. Marketing-heavy, competence-light. The YouTuber's choice. Someone from the project will probably turn up and shout at me below for giving it a less than perfect review.
All of these options aside from the BlueSCSI do termination competently and you won't have to worry about it. You don't have to worry about it on a BlueSCSI either so long as you don't want to attach any other devices.
 

3lectr1cPPC

Well-known member
Worth noting that recently most BlueSCSI v1 devices have been discontinued and replaced with a new V2 version. It’s significantly faster than the v1 and can supposedly max out the SCSI bus on most 68k macs, certainly on an SE/30. Also handles termination with bus transceivers so it should be much better in that regard. A bit more expensive than v1 but much better built it seems.
 

joshc

Well-known member
Also worth noting that ZuluSCSI and BlueSCSI both have CD-ROM emulation like the MacSD now.

My preferences are SCSI2SD and ZuluSCSI for their excellent hardware design/reliability and feature set.
 

Macobyte

Active member
Main ones available now to my knowledge, each with different tradeoffs:
  • MacSD: extremely feature-rich, especially with features for CD-ROM gaming and easily getting stuff on and off that isn't in disc images. I mostly find myself using mine with early Power Macs, because that's where the features have been most useful to me. Competently designed and built in both hardware and software terms.

  • ZuluSCSI: Successor to scsi2sd. Significantly less featureful than MacSD but, in my unscientific experience, a bit more raw performance. Again, competently designed and built. A decent successor.

  • Scuzznet: A bit of an outlier; primarily a SCSI to Ethernet device but it will also do disk emulation. I've mostly used these in 000s to give them Ethernet.

  • RaSCSI/PiSCSI: The Mac fork of this was recently renamed to PiSCSI (IIRC). To me, this has always felt less like a drop-in drive replacement and more a 'SCSI device construction kit'. It's cool if you like fiddling with things, and it's almost infinitely configurable, but that means that as a "drop-in" device it's somewhat less successful. Swings, roundabouts.

  • BlueSCSI: It's cheap and you can build one at home, and beyond this it has almost nothing to recommend it. Dodgy hardware and there are strange timing glitches in the software. Termination isn't done properly. Usable in a 000 if you treat it as disposable. Marketing-heavy, competence-light. The YouTuber's choice. Someone from the project will probably turn up and shout at me below for giving it a less than perfect review.
All of these options aside from the BlueSCSI do termination competently and you won't have to worry about it. You don't have to worry about it on a BlueSCSI either so long as you don't want to attach any other devices.
You don’t list SCSI2SD as an option here. Are they all discontinued? I have a v5.2 in my SE/30 and I like it fine although it was cumbersome to set up and lacked some of the emulator-portable disk image features of BlueSCSI at the time which came out shortly after I bought it. Perhaps for these reasons it’s been discontinued and replaced by ZuluSCSI.

Your glowing praise of MacSD is the first time I’ve ever seen anyone even allude to having used one. I was aware it existed but I’ve never encountered anyone who owned one.

Aside: The drama that erupts here sometimes between ZuluSCSI and BlueSCSI… it’s like having a flame war over what brand of laundry detergent you use. Is there a thread somewhere which objectively documents what about the BlueSCSI exactly is poorly engineered and explains in layman’s terms the risks to our systems? It’s an attractive product but I don’t want to buy one in the future if it’s not well made.
 

avadondragon

Well-known member
In the simplest terms - the original BlueSCSI didn't implement termination properly. They couldn't be used in a chain with other devices and they can burn out. Aa far as I know they aren't a danger to anything but themselves. There have been improvements in the design recently and the newer versions address those issues.

Also yes the original SCSI2SD's have been discontinued.
 

Juror22

Well-known member
You don’t list SCSI2SD as an option here
I don't think it's possible to buy them right now (unless you get the second-hand, because from my understanding the chips they were based on became unobtainable), so they are not really an option (does anyone have them in stock?). I agree that they work well, but also agree that they are a little difficult to set up (compared to the other available choices) and also comparatively more difficult to use with files, so I can see why cheesestraws left them off the list.

Your glowing praise of MacSD is the first time I’ve ever seen anyone even allude to having used one. I was aware it existed but I’ve never encountered anyone who owned one.
I too was aware of them, have a page bookmarked and the only reason that I haven't picked up a couple is being involved with other projects and the cost. The MacSD is one of those things on my wish list, so I was happy to hear a bit more about it and how it was differentiated, particularly with their excellent support of CD images.

Yeah, not going to get sucked into the BlueSCSI/ZuluSCSI thing, but I own several different SCSI emulators and they all have their strengths and weaknesses, but it looks like BlueSCSI v2 might actually deliver on what the original did not - speed, a better codebase and they promise to keep the cost down (if it can remain available). ZuluSCSI also has an RP2040-based version that has come out, so it looks like someone is eventually just going to have to have a 'drive-off' between the two. :)
 

joshc

Well-known member
You don’t list SCSI2SD as an option here. Are they all discontinued?
5.1 is discontinued. V5.2 and V6 are out of stock due to chip shortages. ZuluSCSI is available instead, made by the same company, I think in some cases it outperforms SCSI2SD as well.

Your glowing praise of MacSD is the first time I’ve ever seen anyone even allude to having used one. I was aware it existed but I’ve never encountered anyone who owned one.
I use a MacSD in my Quadra 700 (which is actually a 650 because I put my 650 board in there). It works really well. Easy to setup and well designed.

I am pretty sure someone, might have been @cheesestraws , did a write-up/review of their MacSD when they got it. I did a search but couldn't find it.

What I can also really recommend, if you can get ahold of one, is the mini/external version of SCSI2SD or ZuluSCSI because that means you have a SCSI 'drive' you can pop into the DB25 port at the back of any SCSI-capable Mac which just makes life much easier when you need to quickly install something. It's how I do most of my OS installs on old Macs - my SD card has multiple Mac OS installers on it and tons of software.
 

lobust

Well-known member
I have a SCSI2SD V6 and recently purchased a ZuluSCSI RP2040 and can happily recommend both.

I haven't done extensive testing with the ZS yet, but I suspect that the SCSI2SD V6 is still the best raw performer. Not relevant unless it's connected to a fast bus like a Jackhammer or SEIV - both are faster than the bus on most Macs.

The ZS is easier to work with, using disk images on a FAT32 formatted SD card, vs the lower level device emulation of the SCSI2SD, which requires a special application to configure it.

Both have solid hardware design with physical bus transceivers and share the same form factor so are interchangeable on whatever bracket or enclosure you have for them.
 

cheesestraws

Well-known member
You don’t list SCSI2SD as an option here. Are they all discontinued?

I'm not sure if they're technically discontinued, but the microcontroller needed to build them is currently unobtainium, as I understand it, so even if they're not technically discontinued, they're not an option at present.

The ZuluSCSI is essentially the successor to the scsi2sd anyway, and the user experience is rather nicer.

Your glowing praise of MacSD is the first time I’ve ever seen anyone even allude to having used one. I was aware it existed but I’ve never encountered anyone who owned one.

Quite a number of people here have them! And they deserve to be better known, to be honest. They've got a unique feature set and some of the directions the designer has taken the software in are really cool. The MIDI synthesiser makes me happy, for example, and there's a utility for it to copy files directly from the SD card to get files onto the mac without having to wrap them in a disc image first, which is a really really sensible feature for a thing like this to have. It also has some of the best error reporting through LEDs I've seen, which is always a pleasure.

It has its downsides as well: its power connector is annoying, and the SCSI connector being in the middle of the board means that sometimes the stock cables won't fit and you need longer ones. To me, those are niggles rather than serious problems, but your use case may, of course, vary.

That was necessarily brief: I wrote a thread a while ago called "MacSD trip report" as a kind of semi-review when I first got mine: there's been a lot of movement on the firmware since then and IIRC the software stuff I noted as a bit annoying has since been fixed. Unfortunately you can't fix connector positioning by means of a firmware update. Wouldn't these projects be easier if you could do things like that...

Is there a thread somewhere which objectively documents what about the BlueSCSI exactly is poorly engineered and explains in layman’s terms the risks to our systems?

Sigh, I was hoping to avoid this. I will be brief, because it's exceedingly unpleasant to be bombarded with vitriol in public and private for quoting from datasheets, and I have other walls I need to hit my head on repeatedly today. These comments apply only to the BlueSCSI v1: I am told the v2 is better as it's basically a ZuluSCSI clone: I have not yet tried it.

I certainly want to be clear that as @avadondragon says, there is no known risk to the system you put the BlueSCSI in. They are safe to install and use for the computer. They're not going to destroy any hardware except themselves, and I want to be very, very clear on that point. They're not dangerous.

The risk is the other way around: because of the amount of current that SCSI demands SCSI devices be able to handle, the microcontroller is being overdriven. There is much more current passing through the microcontroller than it is rated for, and that will, over time, damage it. It's not going to die immediately, but slow damage to the microcontroller will occur. I've posted about this in enormous detail elsewhere: I don't want to go and find it because it's followed by several pages of BlueSCSI designers shouting at me, it's only 10am here, and I need to save my capacity for despair for work.

There are other issues as well: termination isn't done right, and I'm fairly sure there are timing bugs in the firmware that limit compatibility. I've not dug into the latter, and again, I probably won't. Those are more easily workable-around though if you use the thing in the intended way.

So, if you're prepared to treat the thing as essentially a disposable item, because it's very cheap, and keep a spare in a drawer and just sigh and swap it out when it melts, and not use it with other SCSI devices, that's a way you could do this. It'd work. Personally I don't have the patience for that kind of thing, but some people do. And if that is the option that is financially accessible, then it is an option, at least.
 

Macobyte

Active member
Thanks everyone for your replies! This is all good to know. We’re spoiled with so many drive emulation options for our old computers.
 

Juror22

Well-known member
Zulu is now offered as a kit option as well if your up for soldering on your own headers you can save $10 bucks off the price of a fully assembled one.
I saw this yesterday and thought that is really great, I'm up for that! (I usually solder on the extra power and led pins anyway, so a little more soldering would be nice)
 

smrieck511

Well-known member
In the simplest terms - the original BlueSCSI didn't implement termination properly. They couldn't be used in a chain with other devices and they can burn out. Aa far as I know they aren't a danger to anything but themselves. There have been improvements in the design recently and the newer versions address those issues.

Also yes the original SCSI2SD's have been discontinued.
Burn out like actually heat up too much or even catch fire?
 
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