[DevilMaster]

I have read the article at https://www.gamingalexandria.com/wp/2019...4-and-sgi/ . At one point it says:

The demo will fail if you use the XFS file system on your workstation due to an error in old IRIS Performer libraries. Mount (read-write) an EFS volume to /mnt (or any other mounting point) and use ‘export PFTMPDIR=/mnt’.

I have asked around about the EFS file system, and I got the following answer:

Never heard of it.
Wikipedia says it's an ancestor of XFS which I've been using for decades, but they're not compatible.
The best thing seems to try NetBSD.
Judging by the commits to the source code, it is well up to date, last changes 22 months ago. http://cvsweb.netbsd.org/bsdweb.cgi/src/sys/fs/efs/
For an obsolete FS it means it is supported, so NetBSD 9.x or 10.x on recent machines or virtual machines, e.g. VirtualBox.

So I installed NetBSD 10.0 on a VirtualBox virtual machine, downloaded the demo ISO, unzipped it and tried to mount it. Result:

mount: Unknown special file or file system `SGI-Nintendo-Ultra-64.iso'

Is there really no hope without an SGI machine? I'd like to explore the assets and see what I can do with them.

[jpstewart]

What was your exact mount command?

I don't know about NetBSD, but on my Linux boxes you need to specify the filesystem type with '-t efs' in the mount command line. Autodetection won't work. The mount command will report "wrong fs type, bad option, bad superblock" if you don't add the '-t efs' explicitly.

Perhaps there's a similar issue with NetBSD not being able to autodetect EFS.

[DevilMaster]

What was your exact mount command?

I started with a simple "mount SGI-Nintendo-Ultra-64.iso" and got that error.
After reading your reply, I tried "mount -t efs -r SGI-Nintendo-Ultra-64.iso" and got the usage line with all the options listed, which makes me think I'm not using the correct syntax, but I don't know what I'm doing wrong.

[jan-jaap]

Code:

$ sudo mount -o loop,ro -t efs SGI-Nintendo-Ultra-64.iso /cdimage

$ ls -l /cdimage/
total 6
-r-xr-xr-x 1 root root  90 Dec 18  1995 CDgrelnotes
-rwxr-xr-x 1 root root 3218 Dec 18  1995 CDrelnotes
drwxrwxrwx 2 root root  512 Dec 18  1995 dist
-rw-rw-rw- 1 root root  201 Dec 18  1995 RELEASE.info
drwxrwxrwx 3 root root  512 Dec 18  1995 relnotes

(Debian 12)

I would take the N64 claim with a grain of salt. This is a disc image of a CDROM better known as "Impact Demos CD for 5.3 Version 2.0", SGI part# 812-0447-002.

These demos were to show off the graphics capabilities of the then new IMPACT graphics cards for the Indigo2 workstation.

There are three demo installers on the CD: certain impact, impact demos and mekton. Mekton will install on the Indigo2 IMPACT ('MGRAS') and the Onyx with Reality Engine ('Venice') and is a game. You can see it here:


certain impact and the impact demos only install on 'MGRAS' systems. You can probably force-install it on an Onyx because the hardware is more than capable.

I know development for N64 was initially done on Onyx. But this is not a disc with Onyx demos. It mostly doesn't even install on Onyx.

[jpstewart]

I started with a simple "mount SGI-Nintendo-Ultra-64.iso" and got that error.
After reading your reply, I tried "mount -t efs -r SGI-Nintendo-Ultra-64.iso" and got the usage line with all the options listed, which makes me think I'm not using the correct syntax, but I don't know what I'm doing wrong.

You didn't specify a mount point. E.g.,

Code:

mount -t efs -r SGI-Nintendo-Ultra-64.iso /foo

Use any existing (and preferably, empty) directory in place of /foo.

Also, I'll re-iterate that I'm not a NetBSD expert so I don't know if that is sufficient for a loopback mount. On Linux you'd also need '-o loop' in there (as shown in jan-jaap's post) but that is not the right syntax for NetBSD. You may need another option or you may need a different command entirely to setup a loopback device first (equivalent to losetup on Linux). Perhaps somebody with NetBSD knowledge will weigh in on that.

[DevilMaster]

Code:

$ sudo mount -o loop,ro -t efs SGI-Nintendo-Ultra-64.iso /cdimage

Thanks. I tried with Debian, with that command line, and was immediately successful. Although now I wonder why it was not dumped in the standard ISO9660 format.

[weblacky]

Because several people have been gently trying to tell you that SGI CDs are almost never formatted in the ISO9660 standard to begin with. It wasn't saved in standard it was never written in.

People often mark the CD images as ISO to indicate the image is an image that can be burned. You could just as easily have put a .Img or .dd extension, but then people would keep asking questions on how to burn it and then you'd have to explain that when burning a whole/raw disk image that the file extension doesn't really matter and the extension doesn't indicate image format in this case, it's just a raw image. No one wants to keep explaining that so we still mark stuff as ISO so you'll at least try to burn the image, it will burn successfully, and then you'll only ask why it's unreadable, not how to burn it and why it's unreadable.

Many UNIX OSes, including Solaris, use CDs specially formatted in 512 byte blocks, often with a company-specific file system to accomplish this. While the reason for it originally was for a BOOTABLE/READABLE optical discs when in station firmware that makes the optical media/device appear similar to a normal 512-byte block hard drive to load the OS. But for non-bootable CDs they started doing the special formatting as well so they could use longer file names, symlinks, other special features not available in ISO9660 and so you had to have the correct computer to read it (back then) so it was unreadable in a pirating PC (you could copy it bit by bit though via duplication/imaging).

The ISO9660 file system was very basic, we've had improvements with extensions since then that didn't exist back then. But it was easier to format using their EFS file system to get more abilities while also making it more difficult for other platforms to read it.

[jwhat]

HI DevelMaster,

if you have an IRIX CD you wish to mount on an ubuntu box then:
0. make sure you have xfs file system utils installed
1. dd to create image of CD on disk
2. loop mount it

So for any current Ubuntu release:

Code:

# sudo apt install xfsprogs
# sudo dd if=/dev/cd0 of=irix-cd-01.img
# sudo mkdir /mnt/IRIXCD
# sudo mount -t efs -o ro,loop irix-cd-1.img /mnt/IRIXCD
# ls /mnt/IRIXCD
CDgrelnotes  CDrelnotes  dist  installtools  relnotes  stand  WhatsNew

The reason you are using type efs rather than xfs is because efs preceded xfs and to maintain compatibility for older SGI/IRIX machines CD were always written as efs image.

Cheers from Oz,


jwhat/John