vt278

On Fri, 18 Mar 2005 10:14:57 -0800, vrs <vrs at msn.com> wrote: The version of OS/8 for that board is termed "OS/278" - there are some fundamental differences with how that design implements the console IOT instructions and how those same instructions were implemented on older machines. As a result, most code that talks to the console terminal needs to be updated to work with any DECmate. It's a trivial change to the code, but if it is not done, IIRC, old code either clears the recently sent character or fails to notice that a new character is available or something equally dire. In any case, unmodified OS/8 will not work properly on a DECmate. Not as far as I know... the console firmware expects a certain device environment to be present. Now... unlike the later DECmates, it _might_ be possible to tap off of the CPU board the right signals to talk to an external terminal, but it won't be off the printer port. It wouldn't be the right device pair (03/04), anyway, for applications to work. The part I don't remember is how much of the VT100 circuitry is on the DECmate I CPU board... In the case of a VT103 (with a _real_ Qbus), 100% of a VT100 is present inside the case, and there's an optional internal card to plug into an odd white socket on the VT100 board that lets you reach internal signals, removing the requirement for external serial cabling for the CPU in the VT103, but the DECmate I is not the same design. If one establishes how much of the VT100 part is on the CPU board, one could make a better determination about how much stuff has to be hung off the DECmate I board to make it work. Since I think the DEC keyboard plugs right into the CPU card, IIRC, I would expect that one would at least have to use a VT100-compatible keyboard as a start, but perhaps one could just attach a frequency-compatible mono monitor to the CPU board and have a system. There are other options possible, so many of those edge finger signals are designed to talk to things like the communications option board (4 extra serial ports?) or the RL02 controller. I'd _love_ to get the RL02 controller for my DM I, but I've never seen one for sale. :-( The cable is well documented, and there are two types - one is DC37-to-DB25 for a single drive, another is a Y cable with *two* DB-25 ends. One typically set the DM I on top of a pedestal-mount RX02 setup that has room for one or two complete RX02 mechanisms. It's available with a hang-on-the-front keyboard tray, or a hang-on-the-front (now the side) desktop bracket. I have the desk and desktop bracket with mine. In that configuration, the RX02 drives face the user. From my rummaging around years ago, I am fairly certain that one can dismantle a rack-mount RX02 and install it in a DM pedestal, but I haven't tried that personally. It _is_ all the same parts, but it _might_ need a longer cable harness for internal power. AFAIK, DEC only had one pinout for RX02 signals over a DB25 cable... There seems to be one DB25F-to-Berg 40 board, one or two of which can be found in the DM pedestal, and one can be found in the MINC-11 tabletop RX02 enclosure. So if one has a MINC-11 with drives, one can borrow the drives for use with a DECmate I. WPS-8 was much more commonly used with the DECmate I than any other OS that I am aware of. If you don't need to read WPS disks, I can't imagine why one would subject oneself to such a product for modern production use, but twenty years ago, people did write papers, letters, etc. with WPS-8, and it will still do so today. I would only recommend it as an exercise for the curious... it is not even close to WYSIWYG, and the manuals are quite thick. If you do determine that you could provide power (probably +5VDC and a couple alternate voltages for RS-232 like +/-12VDC at low amperage), and it's possible to tap off some sort of RS-170-compatible video signal, it's likely that you could put this bare board to use as an expansionless DECmate I... if there are any active video circuits in the remander of the DECmate I, though, you'd have to provide them somehow. I suppose one could recode the firmware, but that wouldn't be a simple task to reverse-engineer the ROMs to the point that one could make the necessary changes. -ethan