You correct in that's what it stands for. My understanding is that it is the bigger brother of MDEX, or put the other way round, MDEX is a cut down version of NOS. If you take a look at the MDEX USer Guide, there are a few references to it, in the System Calls section for instance. Not sure about the 'Network' aspect of it, but at the very least I believe it's multi-tasking.
I'm not aware of any connection to DX10, as that would imply MDEX is a cut down version of DX10. Maybe it is?!
A bit more info below from some notes that Stephen gave me. So looks like we have three O/S's, in order of increasing functionality: MDEX, NOS, TXNOS?
(Jim F also said something earlier about the WD SASI card for the PP95)
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Marinchip M9900
This is the enormous box with two 8 inch drives. It worked when last switched on, but has not been run
for about 15 years. Before you switch it on I recommend that
1) You remove all the S100 cards
2) Waggle all the socketed chips to break any corrosion – we had to do this occasionally anyway.
3) Clean the edge connectors – a rubber is good
4) Reinsert the cards
If you have a Variac (variable mains transformer), it would be a good idea to use it to bring the mains
voltage up slowly on the PSU. Thus enables you to detect problems before they are fatal, and allows
electrolytic capacitors to recover. I'm sure that Google will find you a lot more information on bringing
up old computers.
All the software on the box of 8” discs was set up to use the Televideo 920 terminal.
The MDEX is standard. There's a second 64k RAM card in the box and a copy of NOS (Network
Operating System) on the floppies.
If you see references to TXNOS, this is a version of TI's DX10 operating system or API added to NOS.
It got as far as running some of the DX10 software, including TI's Pascal compiler, which was then the
bee's knees for TMS9900 development.
Powertran Cortex
The MDEX port for this box was done on the Marinchip M9900. I remember very little of the hardware.
And I suspect that some of the hardware was scavenged to use with the PP95.
PP95
There's a little documentation. As far as I remember, this came from a Swedish of Finnish company. It's
basically the Cortex circuitry on an industrial-grade PCB and in a proper enclosure.
The E-bus is populated with another 64kb and a controller for a Western Digital SASI card. SASI was
precursor of SCSI. The hard disc is 5Mb or 10Mb unit and I remember that power up was critical – it
could be that the E-bus had to be powered first, but I really do not remember.
