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Author Topic: SCSI CN50 - Options to Backup Old HDDs  (Read 1126 times)


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SCSI CN50 - Options to Backup Old HDDs
« on: March 12, 2024, 10:20:33 AM »

(marginally system 9 questions i guess, but it involves 9.2.2 and my G4 potentially/ultimately,
if that's too off topic for this board feel free to delete tho, sorry)

my g4 is a mdd, single cpu 1.25ghz, with FW400x2

got a bunch of old mac system 7 hdds and syquest disks+drive that connect to my 68k mac thru DB25-to-CN50

i want to copy them for safekeeping onto redundant dvd-r backups

my 68k mac has no usb or ethernet, just scsi and serial port and floppy

i also have a g4 (but it has no SCSI ports/cards as of now) so i have multiple routes for backups and i figured since this forum has users with much experience at this sort of thing, if there were any precautions or problems, or a best method, i could get some help please

as far as i know, i can either:

1. get some newfangled scsi-to-sd/sata thing that's made in small batch (if they aren't sold out already) and hook that into my CN50 chain on my 68k and backup everything onto that, then just make copies from there (but which models would work best with transfering files and preserving resource forks when you want to burn those backups to DVDs on OS9 G4 or maybe windows?)


2. get a SCSI card or Firewire-to-SCSI adapter for my g4 (OS 9.2.2) then hook up my old drives to that and copy onto the G4, then hope i can burn dvd-rs from there

there are probably other options i dont know about?

the other reason i was considering option #1 is because (while i dont really understand how these new SCSI devices can be used) it seems like maybe you could also use them in reverse to present multiple volumes/disk images/cd images to OS7-9 machines instead of having to slowly download/copy everything?  (specifically i saw one example that also had some neat cd audio and midi options but strangely the midi samplerate was some weird 38khz at 13bits or something? never saw that configuration before, other than that it looked cool tho)

  so in that sense a homebrew scsi thing would be more of a useful multitasker than the vintage pci scsi card approach...although since the G4 has slow USB i guess i would still need a faster way to interface with the G4 than just plugging the SD card into a thumbdrive

i have an old scsi card that seems to fit PCI but it's HD50 (not CN50) and i have not yet tested it

so unless there are alternate approaches i havent discovered online i will go with one or some combination of those two options
  never tried this stuff before so just wanted to get expert opinions on it

ok thanks for reading and your advice!

editing post to include that i also considered maybe some form of networking the two macs, but since the 68k only has serial ports for networking and the G4 only has USB/FW/Ethernet, as far as i know that would require adapter that may not have as much longterm usefulness as the other options... but im no expert and could be mistaken?  anyway
« Last Edit: March 12, 2024, 11:32:07 AM by goodoldmacs »


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Re: SCSI CN50 - Options to Backup Old HDDs
« Reply #1 on: March 12, 2024, 02:49:57 PM »

I would approach this problem by finding a way to connect your SCSI devices to the G4. Data preservation means copying data to the newest storage media available to prolong its existence into the future (it will eventually need to be copied again to something newer, if you want to keep it. No preservation is infinite). OSX 10.4 can still read and understand HFS disks perfectly, as well as easily access the underlying sector data to fully capture the entire disk contents if that is desired. It is also easier to capture or copy information using the OSX tools, because they are all built-in to the operating system, which was never true on classic MacOS.
In particular you will want to use "dd", "diskutil", and "hdiutil".
To connect a SCSI card (you don't say which one you have, but a HD50 external connector was common on many cards), you just need a HD50 to CN50 cable which is a very common type. If you can't find an old cable, you can still buy them new from IEC.
You will want to disable any automount process before switching on power to the drives/inserting SyQuest disks. That is because you don't want the OSX machine to mount the disks read-write and change any information on them. Manually mounting the disks read-only will not change any of the data. SCSI devices also have the ability to be hardware write-protected, so that the computer is unable to change the data no matter what kind of mount command is used. But finding the write-protect jumpers in each drive requires reading each drive's manual and opening the cases.

Some 68K machines do support Ethernet and AppleShare, but for the ones that don't, it's not that simple to network them to newer computers. A G4 would require either a GeeThree Stealth serial port, or a gateway device such as a GatorBox or Shiva FastPath or Asanté AsantéTalk. As you probably know, these are not that easy to find. Then you would also need the network adapters and cables, because the two computers can't just be cabled together, they access a shared network media such as a LocalTalk or PhoneNet segment. You can't use a USB-Serial adapter (from the TrippLite support page: "Any software or printer that uses AppleTalk or LocalTalk is not compatible with any USB to serial adapter.")


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Re: SCSI CN50 - Options to Backup Old HDDs
« Reply #2 on: March 12, 2024, 03:08:39 PM »

Using OSX is way too complicated. OS7-9 drives usually are relatively small. I would just drag the mounted drive(s) one by one to the new location on (backup HD/SSD) disk and they will appear there as folders.
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Re: SCSI CN50 - Options to Backup Old HDDs
« Reply #3 on: May 18, 2024, 09:57:54 AM »

thanks for the replies, i could still use some help though

please i would appreciate an answer to this specifically:

what pci card i can find to purchase that is compatible with my G4 MDD and will definitely work on OS 9 (and that have a good chance of working with OS 8.6 using the openfirmware trick)?

cards that will only work on OS 10 wont help, i wont be using that system.

i can find a couple that say they'll work with OS 9 but i definitely want to try the 8.6 openfirmware trick and i really want a scsi that will work in both

thanks very much

edit: just remembered another important thing to ask

all the different scsi plugs just get so crazy like:

68k mac has db25
all the devices connected to it use cn50
macsd uses idc50
and all the pci cards for the g4 use hd50

so i still need all kinds of adapters and one set that would be really useful but i can't find would be a CN50 to IDC50  (that way i could put the DB25-to-CN50 adapter on the back of the 68k, then the CN50 device, then an adapter to the MacSD with its builtin scsi termination as the last device in the chain)

so has anyone ever seen a CN50 to IDC50 adapter?
« Last Edit: May 18, 2024, 10:39:49 AM by goodoldmacs »


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Re: SCSI CN50 - Options to Backup Old HDDs
« Reply #4 on: May 18, 2024, 01:32:41 PM »

There are a great many available on eBay made by Adaptec. Just search for "adaptec scsi Mac"
You don't need anything fancy. A 2930CU should be fine, though youll need an HD50 to DB25 adapter, which are cheap enough. Just be sure it's an actual Mac edition card. They will work with 8.6.
 it's unlikely youll find an cn50 to IDC50 as IDC50 is an internal connector. Iomega made HD50 to DB25 adapters which they included with their Jaz drives so you could hook up normal DB25 cables. I have one myself and it works great. Again, cheap on eBay. Quick search saw ones as low as $13

Firewire-to-SCSI is prohibitively expensive for what you are wanting to do. It would be the most expensive option out of everything you've suggested, because those adapters were rare even when they were being made. They're quite expensive on the secondhand market now.

ZuluSCSI, and its predecessor SCSI-2-SD is a reasonable alternative. There are flavors of the hardware that instead of using an IDC50, have a external DB25 connector.
I have several SCSI-2-SD devices which I use for my music sampler hardware. I have not used ZuluSCSI but from everything I have read, its less easy to use than the SCSI-2-SD was (SCSI-2-SD was discontinued due to part scarcity) but offers more or less the same functionality.

This SCSI card has DB25, so no adapters needed:

iomega HD50-DB25 adapter:

ZuluSCSI with DB25:
« Last Edit: May 18, 2024, 04:49:56 PM by refinery »
got my mind on my scsi and my scsi on my mind
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