Acorn RISC iX

Acorn's UNIX

Center for Computing History logo

This is a disc image of Acorn's UNIX, RISC iX 1.2.1c. Prepared with the assistance of The Centre for Computing History.

With this it should be possible to install on various Archimedes and restore some of the R140/R260 machines that have corrupted installs or failed discs.



RISC iX



Requirements for the RISC iX machine

  • Acorn Archimedes [1]
  • ARM2/3
  • >=4MB RAM
  • MEMC1a fitted (not MEMC1)
  • Acorn SCSI card AKA31/AKA32 (possibly also AKA30 but untested)
  • A SCSI disc with >270MB storage [2], that the contents on will be overwritten [3]
  • Network card AEH50 (Ethernet II) (optional, untested)

For more information read the Acorn Application Note 252 on the RISC iX 1.2 upgrade.

[1] A3xx/A3000 (maybe), A4xx, A4xx/1, A540, R140, R225, R260. Not A5000, A4, A4000, A3010, A3020, or Risc PC or later)

[2] This was the size the disc was imaged from, theoretically RISC iX 1.2.1c would fit in 100MB, but this installation method will no t fit in less than 270MB.

[3] Discs known to work; Quantum Prodrive 270S, Quantum Prodrive 700S, Seagate ST1980N.

Requirements for preparing the RISC iX disc on RISC OS

  • A RISC OS machine
  • Acorn SCSI card AKA31/AKA32 (possibly also AKA30 but untested) (from above)
  • A SCSI disc with >270MB storage, that the contents on will be overwritten (from above)
  • Another RISC OS filesystem (e.g. ADFS or IDEFS with at least 270 MB free disc space.
  • A way to copy the disc image file to the machine (e.g. network or burn to a CD and read from that)

(or) Requirements for preparing the RISC iX disc on Linux (untested)

  • A SCSI card with the ability to plug in 50pin SCSI devices.

Copying the Disc image on RISC OS

  • Download the disc image ZIP 49MB
  • Decompress the disc image, the download is in ZIP format and won't work directly.
  • Copy the disc image to the RISC OS machine that will do the writting
  • Install the SCSI card and drive into RISC OS machine. Making sure that the disc is the only SCSI device on the system.
  • Download, decompress the SCSIwriter program 4KB (ZIP)
  • Carefully follow the instructions included with the SCSIwriter program. Local copy.

(or) Copying the Disc image on Linux (untested)

  • Download the disc image ZIP 49MB
  • Decompress the disc image, the download is in ZIP format and won't work directly.
  • Install the SCSI disc onto the Linux SCSI card
  • Determine the /dev/ device for the drive
dd if=/path/to/imagefile of=/dev/<scsidisc> bs=1M

After disc preperation, setup on the Archimedes

Install the SCSI podule and disc into the Archimedes. The podule should go in the top right podule slot (when viewed from the rear of the machine).

Boot into RISC OS and issue the following commands.

*configure scsifsdiscs 1
*configure scsifsdrive 4

Reboot if necessary to get the RiscIx drive on the iconbar. Run !RiscIx, this makes sure the RiscIxFS module is loaded, which is needed for the following configuration.

*configure device sd0
*configure partition 0
*configure unit 0

You may need to reboot here also (or rmreinit the riscixfs module to pickup the changes to the config).

You should now be able to click on the RiscIx icon on the iconbar and have it boot into RISC iX.

Move loading RISCiXFS to the !Boot system.

If you have a boot sequence make sure loading of the RISCiXFS module (In !RISCiX.RISCIxFS) is loaded at the start of your boot sequence. E.g. with the universal boot, place it in !Boot.Choices.Boot.Predesk.

More RISC iX documentation

Acorn R140 Operations Guide 7.4 MB PDF
Acorn R140 RISC iX User Guide 17.4 MB PDF
Acorn R140 RISC iX X.desktop Guide
NOTE: RISC iX 1.2 does not use IXI's X.desktop but instead has Motif (mwm) and twm.
5.6 MB PDF
R260 R225 A540 Installation Guide 6.6 MB PDF