Software Guide

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This section is still under construction.

Currently the two available Operating Systems available for the machine are Ultrix and NetBSD/OpenBSD. Linux does not yet work on these machines since the DECstation PMAX is not compliant with the standard MIPS machine (and therefore, won't run Windows NT either). Of the two, the BSDs are much cleaner due to the fact it supports shared libraries like other modern operating systems. Grab the NetBSD binary tree from NetBSD's pmax 1.6.2 site or an ISO from NetBSD's ISO site (grab pmaxcd.iso). This cdrom does not boot with my Yamaha CRW-8424S, but my Pioneer DR-U24X SCSI CDROM works, both jumperred to 512 byte sectors.

NetBSD 1.6.2 install notes

Of 24MB it seems 20MB remains after a custom kernel, about 2MB for text, and 2MB for page tables. Another 2MB is used for kernel userspace apps that's counted against the 20MB, leaving around 18MB for user apps. Wow. Didn't know it used so much RAM. You'll probaly want to use a larger percentage of phys mem for user apps (data segments and text), versus file cache.
sysctl -w vm.anonmax=95Anonymous (arbitrary use, mallocs, stack, etc.)
sysctl -w vm.execmax=50Executable/Text Pages
sysctl -w vm.filemax=35File Cache

As said, the PMAX requires CDROM drives that support 512 byte sectors. Most 'normal' PC SCSI CDROM drives won't work for booting (may not work at all!) since they usually use 2048 byte sectors. Fortunately a good number of later drives can be switched between 512 and 2048-byte sectors. Here's some information I found about DEC hardware and booting.

Ultrix seems most happy with DEC drives since its /etc/disktab seems to only have DEC drives specified in it! (Why would DEC want you to buy Seagate or IBM drives???) Other drives can be used if you get the number of blocks on the drive correctly from the system (though Ultrix 4.2+ will autodetect with the rzdisk(8) command), and use chpt(8) to set the partitions. Note that small SCSI drives that don't quite have enough to cover a 16MB root partition and 64MB of swap (i.e. less than 80MB) will end up with a default of negative space for the 'g' partition! This is due to a slight oversight when it starts allocating the default/"compulsory" partitions. Of course, you can use the /dev/rz?c partition to make the whole drive a data drive as well if you want...

Netscape was never ported to the DECstation PMAX. Therefore if you need a web browser for these machines, Mosaic, Dillo, or Arena are the main choices available. They are available in the NetBSD ports/pkg directory. None support Java as far as I know, at the moment. Since the JDK is available in source form for some platforms, it's likely compileable. Note also that if Mozilla was easily portable to PMAX (I'm sure the NetBSD port should work pretty easily?), it will likely run very poorly as 24MB RAM will likely not be enough to do very much. Expect a lot of swapping, it seems to swap pretty bad as it is with just X11 and fvwm2! (Maybe I should install fvwm1 or use twm for my pmax, fvwm2 uses too much RAM.) So probably the best case would be to use these machines as a lightweight (sic)1 X terminal to a more powerful machine. No, Firefox is not 'lightweight'. Am I going to be a masochist and try to compile Firefox, GTK, and other libraries from the NetBSD ports directory? My poor DECstation will be chugging on the compile for WEEKS. Ok, maybe one week 24/7, and I really hope NetBSD will d/l and autocompile dependencies... urk... Gotta get NFS going, My IDE disks are probably quite faster than asynch SCSI-1 CCS disks... So NO.

CenterICQ, a multiprotocol instant messaging program, took 3 days to compile using stock NetBSD options!!! NetBSD 1.6.2 mipsel/pmax binary is here (version 4.10.0). Unfortunately I have a suspicion that ICQ changed their protocol and this no longer works.

Note that you can run Ultrix binaries in NetBSD for the most part, if Ultrix compatibility is enabled.

Anyway, both operating systems support X11, otherwise a graphical browser would be quite useless. Lynx and Apache compile fine on these machines. The latest version of Lynx in the netbsd pkg directory is *SLOW* too, it could only parse its own ports page around 8KB/sec! Now THAT's slow.

Hey! Do you want to read a quick blurb on my troubles with installing NetBSD? Read ma lutte (a mail message I wrote to a contributer to this page) for what I had to go through. Be sure to read the NetBSD installation pages before reading this. Also if a SCSI CDROM doesn't work for you, try another CDROM drive. My CDRW drive fails but my CDROM worked... weird.

Any questions? Send email to the author on the main page (click on the link on the top of this page.)


  • Digital's Ultrix FAQs
  • Ultrix FAQ local copy
  • OS Data: Ultrix
  • OpenBSD if all else fails
  • Karel's PMAX Linux page
  • Linux (incomplete for pmin/pmax) Project
  • Unofficial NetBSD stuff
  • Oh, if you write software for the console of the DECstation 3100, please don't scroll. :) Because graphics is unaccelerated, the CPU is used/wasted scrolling or otherwise updating the video frame buffer. I'm thinking NetBSD should do jump scroll on the console, it would work better... maybe this would be a good patch for me to do...

    1Hah. These DS3100s are built like tanks and weigh like 20 to 30 pounds without drives in them. It's like 60-70 lbs if you count that expansion unit with two RZ5x's in it. Oh wait, that _is_ the RZ5X unit. The monitor's no lightie either.