Remembering my high-schools first computer a Research Machines 380Z

Technical specifications

Hardware

CPU: The 380Z uses the Zilog Z80A microprocessor with a 4MHz clock.

RAM (Random Access Memory): The 380Z has sockets and circuitry for two blocks of dynamic RAM. Each block can use either 4K or 16K bit devices. 4K and 16K blocks can be mixed. Thus the basic 380Z can be supplied with up to 32K socket on one of the circuit boards.

Printer interfaces: The SIO-1 interface card is available to provide RS232 or 20mA current loop standard serial input output to serial peripherals.

Input/output support: cassette I/O can be selected to be at 300 or 1,200 bits/second. Output to the VDU is at a speed equivalent to about 5,000 baud with automatic paging, which can be suppressed. Output routines are included for the SIO-1, 2 and 3 interfaces and for the Centronics Line Printers.

Hard-copy: Three printers are available. The Centronics 701 is a 132-column dot matrix printer which uses ‘intelligent’ bi-directional printing to achieve a throughput of about 60cps. The Centronics 779 is an 80-column dot matrix printer with a throughput of about 30cps. The Trend 800 is a quiet, lightweight (11kg) printer with a 30cps throughput. It uses standard Teletype paper.

Disc system: Floppy disc systems are being developed along with the requisite software.

Software

RML 9K Basic: Size approximately 9K bytes; suggested minimum size of memory, 16K bytes; precision 7 digits; floating point. Commands, keywords and functions:

This is a fast general-purpose Basic interpreter with floating point numbers, string-handling functions, graphics, re-numbering and line editing. Extensions support the 380Z graphics and allow the plotting of symbols, characters and numbers. Two versions are available, the larger including also the ability to read and write data files on cassette, utilising the RML cassette file system.

RML 12K Basic: Size, approximately 12K bytes; suggested minimum size of memory, 20K bytes; precision 12 digits; floating point. This includes all the features of RML 9K Basic with additions. Lines may be formatted. AUTO line numbering. a RAM can follow every statement, MID$ can be used to insert a substring into an existing string. PRINT USING statement for formatted output—options, right-justified, numeric fields, decimal point alignment, floating £ sign, commas every three digits, string field specification. Hexadecimal constants. Substring search. Enhancement of user-defined functions (multi-line, recursive). Program loading under program control. COPY, EXCHANGE, CALL.

The RML 12K Basic will be of use in business and scientific applications requiring features not found in the RML 9K Basic. Due to its 12 digit precision, however, RML 12K Basic is not as fast as the RML 9K Basic. Graphics commands will be added to 12K Basic in late 1978.

RML 2K Tiny Basic: Suggested minimum size of memory, 4K bytes; precision: INTEGERS only. Range +32767 to -32767; commands, RUN, LIST, NEW, OLD, SAVE. Keywords: REMARK, LET, INPUT, PRINT, PLOT, IF, GOTO, GOSUB, RETURN, FOR, NEXT, STEP, GRAPH, TEST. Functions: ABS, RND, SIZE. This is a small, powerful, integer Basic adapted from Li-Chen Wang’s Palo-Alto Tiny Basic for the 8080. The original 8080 code has been streamlined to use Z80 codes and graph plotting with 380Z VDU graphics has been added. This is a Tiny Basic for graphics, games and learning Basic programming.

RML Interactive Text Editor: Suggested minimum size of memory, 8K: This is a character-orientated text editor comparable to text editors available on large mainframes. The editor responds to a command string which can include commands to locate, delete, type and insert characters and lines, and to move an internal pointer. A command string can be saved and executed as a Macro.

In the interactive mode, normal editor operation is continued and uses four scrolling lines at the bottom of the console screen. Whenever a command string is terminated, text either side of the pointer is displayed immediately on the upper 20 lines of the screen. Portions of the command string can be repeated n times using brackets—brackets can be nested up to eight levels. The editor also includes an immediate mode.

RML Z80 Assembler: This is an absolute assembler using Zilog mnemonics and producing object code in either the industry-standard Intel format or the RML binary format. The assembler incorporates a number of special features to speed program development on cassette-based systems.

Source text is copied into memory during the first pass: the second pass can be made using this stored copy, bypassing the relatively slow process of re-reading the source from cassette. Errors can be corrected using a co-resident editor which implements a subset of the commands available in the RML text editor. Larger programs can be assembled in stages in a similar manner, if desired, or in the normal line by line fashion.

Utilities: Supplied free with all 380Z/280Z systems. Diagnostics, Memory, cassette.

Prices

A 3K ROM Monitor is supplied as standard. The 380Z may be supplied without a keyboard. For cost of the 380Z without a keyboard, subtract £159 from the above prices.