digital equipment corporation · maynard, massachusetts
ETOS is a interesting operating system. It implements a virtual machine allowing multiple users to appear to be in control of the PDP8. The system supports up to 16 users on a less than 1 MIPS machine and 32k words of memory.

Each user logs in and then appears to have a PDP/8 with up to 20k words of core and access to both public and private disk space. Each user can be running a different program or even operating system in their virtual machine. The operating system prevents users from doing operations which would cause problems with the other users. If they execute a halt only their virtual machine is halted. The 6xxx I/O instructions are processed by the operating system so I/O can only be done to resources allocated to that user. ETOS requires a special board which adds/modifies the behavior of some of the processor instructions.

I have three ETOS images available, the first is etosv5b-pl5-dist.rk05 which is a direct copy of the master pack and needs to be configured to run.  etosv5b-pl5-config.rk05 is configured but is almost full with distribution files.
etosv5b-demo.rk05 has unneeded files removed and two demo users accounts created.  Load one of these on
RK05 drive 0 to play with.

To run ETOS run the normal RK05 bootstrap which puts you in a standalone OS/8 session. Run etos (R ETOS) to start the operating system. Hit return at the option prompt.

To login enter LOGIN and then hit return which should then give the login prompt.  No prompt will be displayed for entering the login command. At the prompt enter account number such as 0,3 and hit return. Then enter the password at the password prompt. On the distribution ETOS pack the following users exist:

Account Password
0,3     OPERATOR
0,4     DOCUMEN
0,5     DIFFER
0,6     DEVICES
0,7     ETOSCSP
0,10    ASSEMBL
0,11    STANDAL

On the ETOS demo pack I deleted accounts 4-11 and created user1 and 2. User 1 is a privileged account with 12K default core, user2 is non privileged with 8k default core.

 Account Password
0,4     USER1
0,5     USER2

To see the multi user you can try logging into one of the accounts in each console and running programs.  For

(All the public files are on SYS:)

You can To shutdown enter
. ^VS      (^V is control-V)
!PRIV 4040

I don't have an online reference of the ETOS special commands as html, you will need to print the tiff manuals.  The online OS/8 command reference covers many of ETOS commands since ETOS is based on OS/8.

Other operating system help and links to main help

Feel free to contact me, David Gesswein djg@pdp8online.com with any questions, comments on the web site, or if you have related equipment, documentation, software etc. you are willing to part with.  I am interested in anything PDP-8 related, computers, peripherals used with them, DEC or third party, or documentation. 

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