[author : Jim C. Warren, Jr., Editor] #Computer #Review
Extract : « [...] We would like to apologize to Heath and to our readers for having published what is beginning to appear to have been an inaccurate and poorly researched “evaluation” of the H-8. It is no more appropriate to publish an inaccurate negative article concerning a product, than it is to publish an inaccurate article that praises a product. Articles are written by individuals, and evaluations require judgment on the part of the individual doing the writing. In this case, it appears that the author of the article erred in significant aspects of his judgment, and that we erred in trusting his judgment. For this, we apologize. »
[author : Carl Moser] #Listing #Assembly #Diagnostic
Extract : « Enclosed is a source listing of a program which tests RAM memory in 6502 based systems. I wrote this test after using other memory test programs which did not perform a complete test. The problem areas were untested chip selects, and address line inputs. This program written in my assembler’s source syntax (advertised in Vol.2 No. 8 of DDJ), performs an exhaustive test of a user specified range of memory. The I/O is arranged for 6502 TIM based systems but can be easily changed. »
[author : Craig A. Pearce] #Computer #Review
Extract : « [...]The H8 HAS to be the worst 8080A microcomputer out. Mine, running with 24K at the moment, actually runs correctly when switched on! No self respecting home computer should do that. It even had the audacity to come up running immediately after I completed building it! What will all the tinkerers do with a system that actually runs ?
Unlike the original S-100 bus system I first built, the H8 can’t destroy memory contents when a reset is performed. The damn thing keeps preserving what is in RAM. Furthermore, if you can believe it, this poor machine doesn’t even let the novice write his own bootstrap program to use the cassette interface... one is already in ROM ready to use for loading or dumping. Some spoil sports these Heath people are, aren’t they? [...] »
[author : Stephen P. Smith]
Extract : « I have just become the proud owner of an Ohio Scientific Challenger with Basic in 8K of ROM and a monitor in 1/2K of PROM. While I am delighted with its performance, I’m not happy about the lack of documentation provided for the read only memory. I’d like to use the utility routines which must be buried there. [...] »
[author : Webb Simmons] #Programming #Assembly #Method
Extract : « There are a few simple rules that can be applied to your assembly language program which will show whether your program satisfies the more important criteria to qualify it as well structured in the sense of the modem buzz words on the matter. This presentation is intended to be practical, whatever that means, rather than theoretical ; therefore, I can make, and get away with, all sorts of idiotic statements.
The tools you will need are an extra program listing you can mark up and two colored pens or pencils, say red and green. These pens will be used to connect program branches, jumps, skips, and other transfers from the transfer instructions themselves to the points of reference, the destinations of the transfers. Here we must make a nice distinction between the direction of the transfers so thus the two colors, red and green. »
[author : Perry C. Hutchison] #OperatingSystem
Extract : « [...] ISIS (Intel Systems Implementation Supervisor) is the floppy disk operating system developed by Intel Corporation for the Intellec MDS microcomputer system. ISIS was written entirely in PL/M, a dialect of PL/1 oriented to the 8080 microprocessor. The ISIS system is exceptionally well designed; it bears significant resemblance to Bell Labs’ UNIX operating system for the PDP-11.
Intel has released neither the source code nor any internal documentation concerning ISIS. Since a knowledge of the internal workings of such systems is occasionally needed if they are to be utilized to the full extent of their capabilities, a study of the object code was undertaken. This document contains the principal findings of that study. It should be useful both as a reference for use by persons having occasion to deal with the internals of the ISIS system and as an educational example of what really goes on in a small single-user operating system. Names used are taken from the published ISIS documentation where appropriate [...] »
[author : Ancelme Roichel] #Languages
Extract : « The SAM76 language combines into a single interpretive processor characteristics of two different string and general purpose macro generators and one (or more) infix operator mathematical systems.
SAM76 was primarily inspired by the "M6 MACRO PROCESSOR" designed by M. D. Me Ilroy and R. Morris of the Bell Telephone Laboratories. A description authored by Andrew D. Hall is given in the Bell Lab. Computing Science Technical Report #2, and other places.
The second source of inspiration came from the syntax of "GPM - a GENERAL PURPOSE MACRO GENERATOR" described by its author - C. Strachey. [...] »
[author : Don Van Dyke] #Listing #Assembly #Programming
Extract : « This is a guide for the use of the following disassembler. This disassembler performs most of the work of creating a file, but may require human help in the case of lookup tables. [...]
Exam
1. This program allows the user to examine the contents of memory, and is very useful in locating tables and text in memory when used in conjunction with ADUMP.
2. To use this program, load it into memory and execute it at the beginning. What you will see is the first 1k of memory. To advance to the next 1k segment, press the up arrow (or ctrl-W), to back up to the previous 1k segment, press the down arrow (or ctrl-Z). To advance 8k at once, press tab (or Ctrl-I). To exit to SOLOS or CUTER, press escape.[...] »