Help me! Before I take the plunge

On Apr 1, 2005 5:27 AM, Glen Goodwin <acme at gbronline.com> wrote: Yeah. It's a beautiful specimen of early 80s DEC engineering / Well that depends on who you're talking too. These are I think the only 3 docs available online for the DECmate (VT278) system. http://www.bitsavers.org/pdf/dec/pdp8/cmos8/MP00900_VT278_may81.pdf http://www.bitsavers.org/pdf/dec/pdp8/cmos8/MP01237_278sys_jun81.pdf http://pdp-8.org/scans/an/ek/ek-vt278-hr-001.pdf It runs OS278, different enough that AFAIK most OS8 software won't run. The incompatibilities is mainly due to the non-standard non-OMNIBUS hardware boards that it uses. The below is a part of Doug Jone's superb FAQ on PDP8 and it's variants. <incompatibilities> A new feature was introduced in the 6120 microprocessor: The Group I OPR combination RAL RAR was defined as R3L, or rotate accumulator 3 places left, so that byte swap (BSW) is equivalent to R3L;R3L. RTR RTL remained a no-op, as in the 6100. Also, the EAE operations not implemented in the basic CPU cause the CPU to hang awaiting completion of the operation by a coprocessor. Unfortunately, no EAE coprocessor was ever offered. The printer port offered software baud-rate selection compatable with the VT78 baud-rate selection scheme. The dual-port data communications option was flexible but completely incompatable with all previous PDP-8 serial ports. The console and printer ports are not fully compatable with the earlier PDP-8 serial ports. Specifically, on earlier serial interfaces, it was possible to test flags without resetting them, but on the DECmate machines, testing the keyboard input flag always resets the flag as a side effect. In addition, on the console port, every successful test of the flag must be followed by reading a character or the flag will never be set again. It was not possible to continue from a halt without restarting the machine. The large amount of device emulation performed by the CPU in supporting screen updates severely limits the ability of the system to run in real time. </incompatibilities> Don't know whether OS278 is available or not or for which media. Have to look for it by yourself. Depends on whether it has the optional DP278 board which provides 2 serial ports. Takes in 3 slots at the back (these are not regular OMNIBUS slots, it's proprietary to the DECmate). Slot 1: CPU board + floppy + printer + keyboard Slot 2: Optional (typically DP278 serial controller) Slot 3: Optional (typically RL278 disk controller) The DP278 and RL278 are quite rare nowadays. If your unit doesn't already have them, you'd be hard pressed (at least your wallet will) to find them. Another one of DECmate's advantage is that: You get a VT100 free! :-) [Caveat: This is only if you have a DP278 board. Otherwise you'd have no where to connect it to the host...] I don't know, but to me: - DECmate 1...wow! Such character, and it's soooo 70s :-) - DECmate 2.. eh? Looks like a PC AT? - DECmate 3.. Is that a computer or an external disk unit? The prints/schematics are available. /wai-sun