scsi2sd best practices

[pcamen]

As I start to go through my rather large collection of Macs and get things working, I am contemplating how to best handle the scsi2sd cards for things like duplication, backup, and best compatibility between host systems.

As I've been searching the web for a good tutorial on backup up scsi2sd cards (probably with dd ...) I came across this tidbit. 

One more very important note to ID setup. Although this is not required, it is highly advantageous to take your SD card and put it into your computer to be able to read, write, backup, or restore it (most often with Chicken Systems's utilities). However, the Mac (that is, OSX and macOS) presents a couple problems. Some of these we don't even understand, but we have found a way to avoid them, and we'll describe that solution below. Needless to say, if you don't address these issues, accessing the SD card on a computer will cause a lot of undesirable and unavoidable side-effects (nag screens, inability to write information, etc.)
 
The solution is to reserve the first 20480 sectors of the SD card for the Mac to write it's own "partition table" and make it think it's "playing by the rules" (when it's actually not). Below are instructions how you'd set up the first ID using the UTIL app.
 
1) Under the "DEVICE 1" tab, set the SD Card Sector to 20480
2) To compensate, set 'Sector Count' to 4173824, which is 20480 less than the 2GB count of 4194304
3) Assuming you are setting up 3 more Partitions, set those (DEVICE 2, DEVICE 3, and DEVICE 4) 'Sector Counts' to the standard 4194304.
4) Don't forget to click the 'Save To Device' button - that saves your information onto the SCSI2SD unit.

 
Does that make sense to anyone?  It would be nice to be able to read and write directly to the partitions on the card from my host Mac, but I hadn't really counted on that.  And from what I understand, the v6 boards and the resultant card formatting (which stores the partition info on the card, not the board) will support that. 

But as I have mostly v5x boards (and some v3 boards) ....

As anyone found the above necessary?

 

[Cory5412]

I haven't heard this advice before. Looking at the document, it looks like the advice is really "for" people using it with synthesizers, and with, in particular, the utility they mentioned, which seems to be of their own design. Perhaps it's literally a wrapper  on something like rawwrite or dd.

What are you planning to do with the SCSI2SD and how are you planning to use it/them?

Are you just dropping one board and card into a given machine or are you planning on swapping it between machines or using different cards on it?

Depending, it might be easiest just to treat the SCSI2SD like a regular hard disk, although if you have the right combination of Macs, you should be able to pop out your SD card and pop it into a newer machine, a couple members here have had success with, I'm presuming, a relatively simple SCSI2SD setup and USB SD card readers on Macs that can r/w HFS. (I haven't tried this myself.)

If your machines are new enough to support networking, I recommend making backups of your data onto a file server, whether that's a newer/bigger (but still old) Mac you have, a QEMU emulation, a Windows 2003 VM or a Netatalk 2 daemon is probably largely irrelevant other than making sure you've got enough space.

 

[nglevin]

Yeah, there's a market where SCSI2SD is being used as either a floppy drive replacement or a zip drive replacement for samplers, and... I don't know where to begin to comment on this. Both of those uses are worlds apart from what you're probably planning on using a Compact Mac for with Apple's classic Mac disk formatting tools.

Mac OS X does try to be clever about formatting FAT12, FAT16 and FAT32 depending on the destination device and its capacity. That could be what this PDF is talking about? Maybe? I have no idea. Samplers are probably reading and writing to FAT storage of some kind. This is all stabbing at the dark.

And if your usage somehow hit at those problems, I'd ask, why would you ever use FAT as primary storage for any kind of Mac? That's asking for trouble.

 

[pcamen]

I am hoping that, in addition to being able to backup the SD drives in case of failure on some regular basis, that I can have a library of setups that I can use for multiple machines.  The thought of installing every piece of software and configuring things like networking over and over (I have a lot of machines) seems tedious.

I'm surprised there isn't a library of drive images generally available with software already installed and things setup, that other's have created.  I've searched for this at various times, but have never found much. 

 

[pcamen]

Here is a handy tidbit:

I suggest that you leave about 50 to 100MB empty (100,000 to 200,000 sectors) un-allocated at the end of your SD card to prevent future issues if you want to backup and restore the contents of your SD card to a different SD card.  As I mentioned earlier the available space on these cards isn’t standard, and can vary by 50 to 100MB.

 

[pcamen]

Something else I figured out today.

I wanted to NOT have too big a device for fear of incompatibility with some systems, but I only had a 4 GB and a 16 GB card.  I wanted an 8GB card. 

So in the SCSI2SD setup, I just make the first device 8GB and left the rest undefined.  That way, I can add another SCSI ID later if I want, or even grow

the device size, but it is small like it want it for now. 

 

[Kaa]

I know this post is a bit old, however, I thought I'd chime in about the above quote from chicken systems. They sell software that translates raw and proprietary sampler formats into pc/mac usable audio formats to be able to load samples into and out of your sampler. (As I understand it it will also do programs and multis?). Seems they also sell scsi2sd's in their own external case.

Because the samplers are formatting the cards in formats foreign to the mac, the mac will need to initialize the sd card before it can be mounted and then read by their software. This is why they suggest starting your sector count higher.

The software is great for backing up your sampler but probably not so much backing up the Mac sd cards.