- Vintage Rare Computer SAGE II 68000 8MHz 512KB of DRAM 5.25" floppies
- Turns on, make sound like it loading and fans working, processor light turns on, no farther tests have been done.
- Selling it AS-IS
- Has signs of previous use, see pictures for details.
- Comes with power cable
- Accessories not included
The Sage II computer was introduced by Sage Technology of Reno, Nevada in 1982. The quick synopsis of the machine is that it contains a 68000 running at 8 MHz and has 512 KB of DRAM. As is obvious from the picture above, it has two integral 5.25" floppies. It had no hard disk (that was left to the Sage IV). External connections included a serial port for communication with a terminal, a serial port for communication to a modem, a parallel port for connection to a printer, and an IEEE 488 port.
There were two versions of the Sage II. The earlier version had full height 5.25" floppies; the later version had half height 5.25" floppies and a corresponding reduction in the height of the box. Another way to distinguish the machines is that the first edition had under bars and over bars on the "II" of "Sage II", while the second didn't have them (see the picture above).
The UCSD p-System
More interesting than the hardware is that the primary operating system used by the Sage II was the UCSD p-System, specifically a multi-user version of p-System IV. The UCSD p-System was an operating system written in Pascal with a lot of standard software for writing/compiling/debugging Pascal programs (compilers for other languages also existed). Eventually UCSD transferred ownership and rights to SofTech, who continued developing it, including the version used by the Sage.
The p-System wasn't a native compiler. The source program was compiled to an abstract stack machine using a pseudo machine language, called p-code. The "p" of "p-System" stands for pseudo. Like Java, the p-code programs were then interpreted by a native machine language program. Although this extra level of interpretation sapped performance, it also meant that the p-System could be (and was) brought up easily on a machine since most of the OS and utility software didn't even need to be compiled -- p-code was transportable across very different machines.
There were four versions of the p-code architecture, and the Sage used the final one, p-System IV. The original p-code architecture could address only 64 KB of RAM. The IV edition was modified to allow up to 64 KB of p-code and 64 KB of data. As the Sage had 512 KB of DRAM, only 128 KB was used by the p-System, leaving 384 KB for running the p-code interpreted and, mostly, a RAM disk.
Reports exist that say the p-code files could be compiled to native code to achieve faster run times for many types of programs.
Other Operating Systems
Although the Sage II was sold with the UCSD p-System as the primary operating system, others were available. One was Digital Research's CP/M 68K. I'm trying to track down information on this. If you have documents or boot disks and are willing to sell/share, I'm interested.
Mr. Marcus Wigan, a long time Sage/Stride user, notes the wide variety of operating systems available for the Sage. Interestingly, the software architecture of the Sage allowed the machine to host multiple simultaneous operating systems; one user could be running Unix and another running p-System UCSD Pascal.
Hyperforth+Cambridge TriposMirage (APL)IdRIS (unix)USCD IVModula 2ListKIT LispPDos (RTOS)The Machine
Externally, the box is simple, attractively so. The front panel has two half height 5.25" disk drives and a single bi-color LED. This LED is green while the CPU is "thinking," and turns red when it is halted waiting for I/O or hits an unrecoverable error. There are no connections or distractions on the top, bottom, and sides. The rear panel has the power jack, the power switch (lever toggle), and clearly labeled ports IEEE 488, printer, modem, terminal, two dip switches, and a reset switch.
Here is what is inside the box.
a sheet metal case 12 3/8" W, 16 5/8" D, 4" Han aluminum shield surrounding the floppy disk drives, presumably to prevent airflow from dragging dust through the drives and perhaps for EMI controla lightweight switch mode power supplyan (incredibly noisy) muffin fan, blowing out the bottom of the casea single PCB containing all system logic. The board has no custom parts, not even any PALs.68000L10 running at 8 MHz512 KB of DRAM, using 72 64kx1 DRAMs (parity per byte)two serial ports driven by two NEC D8251 chips (up to 19200 baud). one serial port was for the user terminal; the other is labeled "MODEM", but the printer could also be assigned to that port, and I believe it was possible to hook up a second user terminal on that port as an option.parallel port driven by NEC D8255the other D8255 is probably used to sense the DIP switches on the back panelIEEE 488 port driven by TMS9914 chiptwo NEC D8253 programmable interval timer chips, for use by the OSNEC D8259 interrupt controllerNEC D765 floppy disk controller (the same type used by IBM PCs)two 2732 EPROMs to hold the monitor program (effectively 4K x 16b). Sage provided for upgrading to larger EPROMs with a 28 pin socket, but only needed the smaller 24 pin 2732. In case you ever need the information, note which socket is even and odd, and how the 24 pin 2732 is aligned in the 28 pin socket.two 50 pin connectors bringing out the system bus for expansiontwo half height 5.25" floppy drives, 96 tpi, double sided, double density, Mitsubishi M4859.