#decpc

Digital DECpc 325SLC (1993)

Digital (DEC) always made interesting computers and their PC laptops were no exception. DECpc 325SLC was a laptop with the first generation of color passive-matrix displays. The picture quality (aside the ability to display colors) was on par with monochrome passive-matrix screens with all the drawbacks they had. On the other side, the computer was equipped with a 25-MHz Intel 386SL and SVGA graphics for just $2.100 – the price where other laptops from most other brands have just monochrome screens and VGA graphics.

The 386SL is the first CPU specifically designed by Intel for use in laptops. It integrates almost a whole PC into two chips, with the main chip containing (among other things) a 386SX core (with 16-bit data bus) and 64kB of cache (16-bit as well). Intel built the platform to support then new power management functions like the sleep mode (“suspend to RAM”). The performance of this CPU is halfway between 386SX and 386DX.

Graphics chip was not integrated in the two Intel chips. Digital decided to use a chip from Western Digital with 512kB of video memory and the support for 256 colors with a resolution up to 800x600. The chip was attached using the ISA bus and had no acceleration. On the other side, the support for VESA VBE 1.2 and ~3MB/s throughput to video memory made it a good mainstream solution among ISA based cards of the time.

Bytefest 2019

These were the computers we brought to Bytefest – a Czech vintage computer show. David and I decided not to bring more than two desktop systems. Amiga 2000 was an obvious choice – we fixed it not a long time ago and I played a lot with it recently. The other computer was SGI Indy with the original set of peripherals including the Indycam camera. There are not many vintage UNIX computers to see on vintage computer shows in this country. Thus, it is my duty to bring at least one every year.

The Aritma Minigraf plotter sitting on top of the Indy was connected using one of the Indy’s serial ports though a special ARM-based module that David built. The module contained the control software that allowed it to draw faster and with better precision than the plotter was originally designed for. From time to time, there were couple of people standing in front of the plotter, being hypnotized by the smooth movement of the pen. The Indy itself was communicating with the module as a serial terminal with the ability to send HPGL files that needed to be drawn.

I’d never played that much with Indy before (aside creating the OpenGL 1.0 version of our 3D graphics benchmark) and this was a nice experience. The graphics card in our Indy is able to display no more than 256 colors (or 16 colors for double-buffered 3D), but it’s pretty fast and allows you to have a different 256-color palette for an active window and the rest of the system. Therefore, the color flickering effects are minimized in comparison with PCs set to 256-color modes. I was surprised by the visual quality of the composite input from Nintendo 64 in 256 colors.

Commodore Amiga 2000 was configured to show the capability of this platform during the late 80s (thus, Workbench 1.3 and Kickstart 1.3 only). It didn’t have any accelerator board and the only expansions were a simple hard disk controller, 2-MB fast RAM card and A2088XT PC emulator (with an 8088 and 512kB of RAM). During the show, I also added an ISA card with a serial port (for Microsoft InterLink purposes) and a VGA adapter.