From simasd!nosc!CRDEC2.APGEA.ARMY.MIL!pvpullen Thu Sep 20 06:05:03 1990 Received: by simasd.UUCP (smail2.5) id AA06672; 20 Sep 90 04:43:43 PDT (Thu) Received: from CRDEC2.APGEA.ARMY.MIL by trout.nosc.mil (5.59/1.27) id AA27298; Thu, 20 Sep 90 04:27:20 PDT Date: Thu, 20 Sep 90 7:24:43 EDT From: "Paul V. Pullen" Ppath: pnet07!donm To: simasd!pnet07!donm Cc: pvpullen@CRDEC2.APGEA.ARMY.MIL Subject: Intertec Compustars Message-Id: <9009200724.aa25505@CRDEC2.APGEA.ARMY.MIL> Don, Intertec manufactured four versions of the Compustar computer. They were equipped for setting up multi-user 'networks' using either a 10 megabyte or 80 megabyte hard drives. They are all equipped with the usual modem and auxillary ports on the back panel, as well as two ~35 pin d-type connectors that attached the systems to the hard drives. Each unit is equipped with an additional board called a chaining adaptor that enables the units to 'chain' together and use the common hard drive. It was a good idea for software, and then had you use a floppy (?) for your data. Intertec's design included the use of a hardware switch on the chaining adap- tor that enabled the system to have a maximum of 255 different 'stations' on the 'multi-user system'. Each station would have its own section parsed out of the hard drive, an individual drive c: assigned to the terminal. If it did not have an 'area' carved out of the hard drive, the system would not allow the station on the network. We used a maximum of 4 stations at one time on our network when it was operational. It seemed to work pretty well. Intertec manufactured the following models in the Compustar line: VPU-10 This model was a terminal only. It required its operating system to be written to the system tracks of the hard drive. There were no floppy drives on these terminals. I guess it would be considered the system console. VPU-20 This model contained either one or two (I never saw one of these) Single sided disk drives. What little I know is from an enhanced piece of software that formatted disks especially for the systems 20,30, and 40. If I recall correctly, it uses drive a: to format the disk, so I suspect that the VPU-20 only had one disk drive. VPU-30 This model comes (or came) in at least two versions. I have samples of each, both personal and government owned. The systems contained two DSDD disk drives, and could be booted either in stand-alone mode (no hard drive) or in networked mode. VPU-40 This model contained the 96 tpi drives. I have never seen one. I will check for ROM versions, but the easy way on the VPU-30 to tell the diff- erence between them that I know is two fold. First, the power supply on the non-enhanced VPU-30 is mounted on the bottom chassis. It is tied together with the main circuit board by a flat cable that is made up of strips of 'aluminum foil' in vynal jacket. It truely is a flat cable. This model of computer uses Magnetic Periphals disk drives (NEVER use a Tandon Drive in this version. The current draw of the Tandon will blow the power supply). The smarter VPU-30 has its power supply mounted on the back of the disk drive cage. It has a larger power supply and was stocked with Tandon TM100-2 disk drives. It needs a different operating system than the non-enhanced. Another difference is the real-time clock battery mounted on the upper right hand corner of the main circuit board. The circuitry is different on the boards, but both would maintain a clock in the upper right corner of the tube. The enhanced would, like the present pc-clone, maintain the time even when turned off. The enhanced version of the VPU-30 was equipped to maintain the time, whether the system was off or on. If I recall, the ROMS never had marks on the outside as to what their ROM revision was. We had problems with this and the hard disk DSS-10's. I have two personal DSS-10's with different ROMS in them. It is terrible to re-initialize. By guess and by gosh I have re-initialized them, but you have to play with the computers to find one that will talk to the disk drives. This is a first run of information that you can store. I will assemble the boot disks and get them out to you as soon as I can put them together. Paul ---------------------------------- Paul Pullen United States Army Chemical Research, Development and Engineering Center pvpullen@crdec2.apgea.army.mil (301) 671-2519 /(301) 671-4174 ----------------------------------