An article from the April 1987 issue of Computer Technology Review: ************************************************************************** * * * * APRIL EXCLUSIVE * * * * Add PC compatability to your Cray via hardware/software inefficiency * * * ************************************************************************** Do you want real functionality from your Cray 4 while you're waiting for the 1990 census figures to come rolling in? Generating 1 million x 1 million pixel weather maps can get boring, especially when there are so many graphics applications waiting to be run, such as pie charts and bar graphs for corpor- ate presentations. PC compatability As PC mania continues, owners of Crays and other supercomputers are faced with a myriad of operational problems. For example: * Cray 4 formatted diskettes aren't available at most Computerland or Business- land stores. * It's difficult to find printer interfaces from the Cray to such popular prin- ters as Okidata and Epson. * Its equally dificult to find joystick interfaces so that Flight Simulator can be played on the Cray. * Some bulletin boards are inaccessable because of the lack of PC-Net or Apple- Talk for the Cray operating system. The real question is: Why be better when you can be the same as everyone else? Now there is a new tool to justify the purchase of a Cray to your boss - PC compatability! CRAY-Z hardware/software package L/F Technologies (Carson City, NV), a manufacturer of multiuser computer systems, has created a new software division dubbed SOFTindaHEAD. The divis- ion's charter is to solve the types of problems that plague owners of more pow- erful business and industrial computers who want to downgrade these systems to PC compatability. A combination hardware and software package called CRAY-Z was announced for the Cray 4 by SOFTindaHEAD on April 1. The package contains all the necessary parts and programs to turn your Cray into a PC compatible system. Rather than go to the trouble of writing efficient software, SOFTindaHEAD has chosen to write a Brute-force Universal Generator for Software (BUGS) to to convert MS-DOS programs to Cray-executable software. This software converts the object code, line by line, to COBOL. Next, the COBOL source is converted to C for portability. Finally, the C source is converted to CRAY object. This en- tire process takes roughly 20 min/Kbyte of code. The reason for not devising a clever conversion algorithm (other than sheer laziness) is to take advantage of the processing power of the Cray. Because the Cray operates several orders of magnitude faster than a PC, adding this signifi- cant overhead slows the Cray down to a crawl so that it can be compatible (see Fig. 1). ***** * * Time spent on * * useless tasks * * * * * 92% * * * * * * * * * * * 8% * * * * Actual processing * * * time available * * * * * * ***** Fig. 1 In order to degrade the performance of the Cray sufficiently to emulate a PC, 92% of the processing time is spent on useless tasks. Memory usage Another important capability of the CRAY-Z software is that it allows you to use the extremely large memory of the Cray. For example, Lotus 1-2-3, con- verted with BUGS, needs 264 Mbytes of RAM to run. You can also imagine how much fun it will be to back up a Lotus file on the double-sided, double-density (DSDD) floppy drive. The hardware components consist of several delay lines to enhance the slow- down feature of the software, and a special Terminal Reduction Assembly and Shorting Harness (TRASH). The delay lines are inserted at strategic locations to prevent useful para- llel processing. Obviously, parallel processing capability would cancel all the work done in the software to slow things down to a level that we're all comfor- table with. The TRASH not only prevents you from plugging in more than one terminal, it shorts out all the associated driver hardware so that only one terminal can work on the Cray. This useful feature created a difficult problem for company engineers. Freeing the Cray from processing multiple-user requests speeds the darn thing up. To prevent this undesirable side effect, a variety of proprietary circuits are installed in the TRASH to keep the Cray busy tracking down faults instead of enhancing its response time. The final hardware component included with CRAY-Z is a 380-Kbyte, SA-450 compatible DSDD floppy disk drive. Along with the drive is a PC form factor controller board and the necessary backplane, mounting hardware, sheet metal, and power tools to install the drive in your Cray. -Jim Zakzeski -------------------------------------------------------------------------------- Single-quantity CRAY-Z packages are priced at $244,500. Contact Jim Zakzeski, CRAY-Z product manager, L/F Technologies, 2800 Lockheed Way, Carson City, NV 89701, call 702-883-7611.