Depending on which system is chosen, the langusEe ~ y be either compiled or interpreted. If it is a compiled language, program preparation and debugging will be more complicated, but they will run faster. With an interpreted language, the situation is reversed. This is the beginning of a new era in laboratory automation. The scientist will now be able to experiment with measurement techniques without investing the time required to become an expert in minicomputer hardware and software. He need only learn a high level language such as FORTRAN or BASIC. THE MOST SIGNIFICANT BITS - - J. E. Godderz Special Area Editor On March 2 1 attended a seminar conducted by DEC (Digital Equipment Corp.) describing their microcomputer, the LSI-11. The LSI-11 is called a minicomputer, but is also sold in two packages which look and act like minicomputers, the PDP-11/05 and PDP-IJ/V05. All three of these computers use the same basic components: a microprogrammed CPU board with 4K words of memory (either core or RAM), optional memory boards to a maximum of 32K words, optional serial and~or parallel interface boards. An additional R0M chip can be plugged into a socket on the CPU board to provide extended instructions for fixed and floating point arith~ metic. There are over 400 machine instructions which are the same as those of the PDP-11/40 mini. Both word and byte addressing are permitted. Eight general purpose registers are provided; one of these is also used as a stack pointer, another as program (location) counter. FU1N & GAMES --Mark R. Crispin Special Area Editor The LSI-11 comes as loose circuit boards and a backplane, starting at $990 for single unit. The PDP-11 consists of the CPU board, backplane, serial interface board, and power supply all in an attractive enclosure with an operator's panel. Price for single quantities is $2495 (RAM) or $2925 (core). The 11/03 is unique because it has no switches on the front panel for entry of binary words. DEC has decided and I think rightly - that many sources of problems exist in the switches and display lights found on the front panel of most minicomputers. Since the only purpose of these lights and switches is the entry/display of binary information DEC has provided a better method of data entry/display and eliminated the switches and lights. Each LSI-11 CPU board is set up for two modes of operation: RUN and 0DT. In RUN mode the machine instructions are executed to produce the desired results. In 0DT mode, "on-line debugging techniques" are available to the user. These 0DT functions include the entry, ex~unination, and replacement of binary data words by typing the appropriate commands on an input terminal. Programs in memory are executed by typing the starting address of the program and the letter "G" for "G0". Thus a program beginning at 1000 (octal) would be executed by typing either "1000 C" or "IO00;G". Not only is ODT easier than using panel switches, but if a printing terminal is used, a permanent record of the memory data is obtained. The PDP-11/V03 is a complete, low cost programming system. It contains an 11/05 with 8K words, a dual floppy disk (512 ~ Bytes), a -4- Minicomputer fun and games is an often scoffed-at topic, but yet is quite important. The STAR TREK game players of a few years ago are quite often now the systems hackers of today. Many young people have gained invaluable knowledge in game writing (and playing!) on their high school's (or even elementary school's) minicomputer system. The games are also getting more sophisticated. Among the hacks I have seen on a PDP-8/e (my system) are a real-time oscilloscope Spaeewar game, a simulation of Conway's game of LIFE, and even a 4K chess program! If you have any news of developments in this field, or even want to show off some hack you wrote, please contribute. We can and will • print ( a l m o s ~ a n y t h i n g short of blatant advertising. My address is on the front cover.

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