Articles tagged with: Retro

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Modula-2 Compilers on CP/M

Modula-2 is a great language in general and is a good choice for programming on CP/M. There are three good compilers available for CP/M which all require a Z80 processor and we'll compare each in turn... Read More

XCCP: A Shell Extension for CP/M

#CP/M
#Retro

XCCP describes itself as an Extended Console Command Processor for CP/M. It supports the 8080 and v1.0 was released by Anton R. Fleig in 1984. Like EPEX, XCCP doesn't require installing so we can begi... Read More

EPEX: An Environment Extension for CP/M

#CP/M
#Retro

Epex is an evironment extension for CP/M. It stands for Environmental Processing EXecutive, and v1.1 was released by James H. Whorton in 1986. It can make using CP/M much more comfortable at the cost... Read More

File Comparison Utilities on CP/M

#CP/M
#Retro

There are many utilities available for CP/M to compare the differences between files and to distribute those differences. All the utilities in this article can be found on the Walnut Creek CD. Binary ... Read More

80 Columns in Software on the Commodore VIC-20

If you have good eyesight, a well-tuned display and patience it is possible to use 80 columns in software on the VIC-20. This is really just an experiment but considering the limitations of the Vic I ... Read More

Breakout Style Games on CP/M

Breakout style video games were pretty popular at one time both at Arcades and on home computers. The games are based on a simple concept where you have to destroy a group of 'bricks' at the top of t... Read More

64 Column Text Mode on the Commodore VIC-20

With a little lateral thinking and by putting the television on its side we can create a 64 column sideways text mode on the VIC-20. This article will demonstrate this and show how it is done. Previo... Read More

Hamurabi and Similar Games on CP/M

Hamurabi is probably the best known land and resource management game on CP/M. However, there are a few other similar text-based games that sought to extend the concept such as Dukedom and Kingdom. T... Read More

Word Processors on the Commodore VIC-20

Word processing is possible on the VIC-20 and can be surprisingly comfortable despite the small screen text area. Here I will show a variety of word processors each of which handles the 22 column rest... Read More

Getting the Address of BASIC Variables on the VIC-20

Getting the address of a BASIC variable can be useful if you want to pass data to a machine code routine or want to access the bytes of a variable directly to improve speed and reduce garbage collectio... Read More

Saving and Loading Memory on the VIC-20

Saving and loading memory is quite easy on the VIC-20 once you know how. However, it isn't obvious how to do this and therefore this article will present a few simple ways of doing it from BASIC and A... Read More

Advanced Use of .LBR files on CP/M

Lots of utilities make use of .LBR (Library) files to provide extra facilities such as the ability to run commands from archives or mount them as if they were drives. This article shows some more adva... Read More

Working with .LBR files on CP/M

The .LBR (Library) file format was the most common form of multi-file archive on personal computers at one time. It was created by Gary P. Novosielski in 1982 for use by his LU (Library Utility) progr... Read More

Basic Line Storage on the VIC-20

BASIC programs are stored in memory using a simple structure that we can investigate and manipulate. This article will show how they are stored and contains a BASIC program to go through each line of ... Read More

Programming in Assembly with VICMON on the VIC-20

VICMON is a machine language monitor released by Commodore in 1982 and is great for programming the VIC-20. Its interactive nature means that it can often be quicker to develop via this rather than us... Read More

Storing Machine Code in REM Statements on the VIC-20

BASIC programs often contain machine code routines but they take up quite a lot of space in BASIC. An interesting way to reduce the amount of space that they take is to store the machine code in REM s... Read More

Re-execute Programs in Memory on CP/M

#CP/M
#Retro

After a transient program terminates on CP/M it's often possible to re-execute it in memory without having to reload it from disk. This is a great little trick if using slow disks as it's much quicke... Read More

Visualizing Zero Page on the Commodore VIC-20

The VIC-20 is a very flexible little machine and allows us to choose which area of memory represents the screen map. One interesting thing we can do is use this to visualize a section of memory such ... Read More

Code and Data in Display Memory on the VIC-20

The unexpanded Commodore VIC-20 only had 5K of RAM and therefore creative ways had to be found to maximize the available RAM. The display memory would use some of this memory and therefore one option ... Read More

I Love ED on CP/M

I love ED on CP/M. It's often derided but I think it's just misunderstood and with a little practise its true value can shine through. It's elegant, easy to learn and only has about 25 commands but t... Read More

Double-Width C64 Style Font on the Commodore VIC-20

The C64 used a fatter double-width font because the video quality of early VIC-IIs wasn't very good. Therefore they had to make the C64's font fatter than the VIC-20's. However, this fatter font look... Read More

The Pilot Programming Language on CP/M

Pilot was created by John A. Starkweather in the early 1960s as a programming language for Computer Assisted Instruction. It has often been compared to Logo because of its use with children. However,... Read More

Walnut Creek CD: C64 Images

The Walnut Creek CD has a number of images on it from the 1980s and this article displays a selection of the Commodore C64 images that can be found on the CD. The quality of some of these pictures is ... Read More

Walnut Creek CD: .RLE Images

#Images
#Retro

The Walnut Creek CD has lots of images on it from the 1980s and this article displays a selection of the .RLE images that can be found on the CD. Where there are duplicates they are only shown once. .... Read More

Image Viewers on CP/M

CP/M is by default a text-only affair. However, many of the machines that can run CP/M have hardware that would allow them to display graphics. As BBSing started to grow so too did the distribution o... Read More

Terminal Programs for BBSing on the Commodore VIC-20

The VIC-20 introduced many people into the world of BBSing, but only a few of the many terminal programs that were available for the Vic have survived. They each have their own pros and cons and here ... Read More

SUBLEQ on the Commodore VIC-20

I have created a SUBLEQ Virtual Machine for the Commodore VIC-20. SUBLEQ is a computer architecture that has only one instruction: SUBLEQ. The instruction stands for SUbtract and Branch if Less than ... Read More

Home Computers: 100 Icons that Defined a Digital Generation

As soon as you pick up this coffee table style book you know that you're in for a treat. A quick flick through reveals page after page of beautiful photos accompanied by well layed out text describing... Read More

The Mouse Programming Language on CP/M

Mouse is an interpreted stack orientated language designed by Peter Grogono around 1975. It was designed to be a small but powerful language for microcomputers, similar to Forth, but much simpler. On... Read More

Sweet 16 (The 6502 Dream Machine) Ported to the VIC-20

Sweet 16 was created by Steve Wozniak to reduce code size and make it easier to handle 16-bit pointers and arithmetic for his Apple Integer BASIC. He wrote it around 1977 and referred to it in an arti... Read More

Position Independent Code (6502) on the Commodore VIC-20

If we are writing 6502 machine code and want to to create a routine or program that can be placed in any location then we have to create Position Independent Code (PIC) or make the code relocatable. H... Read More

Adding Basic Stubs to Assembly Language on the Commodore VIC-20

To make machine language programs more friendly it's nice to add a Basic stub which contains a line with a SYS statement to start the code. This is easy to do on the VIC-20 and the process gives you a... Read More

Hand Assembling to Machine Code on the Commodore VIC-20

I quite enjoy designing machine language routines on paper and then hand assembling them. For many people this would have been their only option until they got a more advanced machine language monitor... Read More

6502 Machine Language Tables and Aids

When programming using machine code there are a few useful aids that can make it easier to do. I have created a couple of tables for the 6502 that can make the process easier. They are based on table... Read More

Tokenize/De-tokenize Commodore Basic Programs Using petcat

petcat is a utility provided with the VICE Commodore emulator that you can use to convert Basic source code contained in ASCII text files to .PRG files or vice versa. It is also able to convert ASCII ... Read More

Changing Screen Dimensions on the Commodore VIC-20

To make the most of the limited amount of memory on the VIC-20, we can increase and decrease the screen size depending on our program's priorities and what we want to achieve. If we increase the size ... Read More

Moving the Picture Origin on the Commodore VIC-20

The VIC-20's VIC chip provides a simple yet flexible video display and one of the features that can be quite useful is the ability to alter the picture origin on the screen. This feature allows us to ... Read More

DABAR: A Hebrew Vocabulary Drill System on CP/M

#CP/M
#Retro

I recently came across an interesting program called DABAR to drill Hebrew vocabulary. The program works in a similar way to flash cards, by displaying a word in Hebrew and then asking for its English... Read More

Spreadsheets on the Commodore VIC-20

The VIC-20 had a number a spreadsheet programs released for it which despite the limited resources of the Vic could actually be quite usable. The two best known are SimpliCalc and PractiCalc, but ther... Read More

40 Columns in Basic on the Commodore VIC-20

There are a number of programs that allow you to use 40 columns of text from Basic on a Commodore VIC-20. This can be useful as by default the Vic's screen is 22 columns by 23 rows. They are supplied... Read More

Backgammon: The Peelgrunt Game of Gammon IV on CP/M

My favourite traditional board game is Backgammon and the best version I have found for CP/M is The Peelgrunt Game of Gammon IV, v2.0 released 1st April 1986 by David C. Oshel. It is available on the ... Read More

DIR Alternatives on CP/M

#CP/M
#Retro

There are lots of great alternatives to the standard CP/M DIR command, which add extra functionality and combine features that normally have to be accessed through other CP/M commands such as STAT or S... Read More

Mission: Impossible on CP/M

Mission: Impossible simulates a foreign espionage mission based on the TV series. Your mission, should you decide to accept it, is to recover the objects or person taken by enemy agents and hidden in ... Read More

Hunt the Wumpus on CP/M

Hunt The Wumpus was created by Gregory Yob in 1973 after seeing some of the hide and seek style games distributed by the People's Computer Company. Games such as Hurkle, Snark and Mugwump were all ba... Read More

CP/M Standard Console Control Characters

#CP/M
#Retro

CP/M helped provide a consistent console interface for the user by supporting a number of standard control characters through the BDOS console functions. This was great for the user and made life much... Read More

Transferring Files to and from CP/M .D71 Disk Images Using ctools

Using Vice to emulate a Commodore 128 running CP/M works very well, but it isn't easy to get CP/M files directly onto and off a .D64/.D71 disk image. The easiest way to do this under Linux is to use c... Read More

Emulating a CP/M System With z80pack

z80pack is great for creating an emulated CP/M system. It can either be used to create a general CP/M system or can emulate a specific system such as an IMSAI or ALTAIR including a graphical front-pan... Read More

Instrument Flight Simulator on CP/M

Instrument Flight Simulator is a text mode flight simulator for CP/M which uses standard ASCII characters to display an instrument panel for the plane. The aim of the game is to land the aircraft safe... Read More

Interactive File Managers on CP/M

#CP/M
#Retro

CP/M has a number of interactive file managers that can be used to make it easier to handle common file operations rather than using the command line driven commands supplied with CP/M such as: DIR, ER... Read More

Felix Animation System on CP/M

#CP/M
#Retro

In 1979 the University of Tennessee/Knoxville's Computer Science Department released Felix v2.1 for CP/M, which is available on the Walnut Creek CD. It aimed to provide a basis for computer animation ... Read More

Compression and Archiving on CP/M

CP/M has the ability to handle lots of different compression and archive formats which was important due to the limited capacity of floppy disks and the cost of downloading/uploading files on BBS's. T... Read More

Text Viewers on CP/M

#CP/M
#Retro

There are lots of text viewers on CP/M and I want to show the three that I use most often. I have recently been going through the Walnut Creek CD to see if I can find any better text viewers, but afte... Read More

Write Hand Man - CP/M's Answer to Sidekick

#CP/M
#Retro

CP/M is a single tasking operating system and having grown-up with single tasking systems this has never really been a problem for me. There is style of program that would make my life easier, however... Read More

Benchmarking Basic on Vintage Computers

There are a few machines I'm quite interested in comparing so I decided to create a simple Basic benchmark to get an idea of their relative speed. The benchmark tests 7 aspects and is inspired by qsbb... Read More

What the Dormouse Said by John Markoff

The premise of this book is that the 60s/70s counter-culture led to the personal computer revolution. I think the book demonstrated well how this influenced SAIL and how the Augment lab innovations led... Read More

Programmable Character Sets: A Simple Alternative to Bitmap Displays

#Retro
#Text Mode

Programmable or reconfigurable character sets were a simple alternative to fully bitmappable displays. The main driving force behind their creation was a desire to keep the cost of computers low: RAM ... Read More

Creating a TTY Simulator in Assembly Language on the VIC-20

The Vicmon machine language cartridge is an excellent tool for exploring the Vic-20. This article and its associated video will show you how to use it to create a simple program that will change the n... Read More

BBS Ads: Getting the Word Out

BBS Ads were important to users and sysops of BBS's. There wasn't any universal directory like the phone book, and during the heyday of BBS's (early '80s to the mid '90s), most people couldn't easily ... Read More

Beginning Assembly Programming on the Commodore VIC-20

The Commodore VIC-20 is a great machine to learn an assembly language on. It was released in 1981 and was the first computer to sell one million units, which contributes to its popularity today. The ... Read More

Using C-Kermit to Exchange Files With Telnet BBS's

Most BBSs that are still running now do so via telnet. In many ways this is great as it allows people from all around the world to access a BBS as if it were local to them. The problem comes though, ... Read More

Connecting to a Remote Serial Port over TCP/IP

Most modern machines don't have a serial port as standard; you could use a USB to serial lead, however, if you have another machine available that does have a serial port you can access it remotely ove... Read More

If Only Borland Had Stuck With Turbo Modula-2 For CP/M

I have written previously about why Turbo Pascal is a Great Choice For Programming Under CP/M and now it is time to talk about what could have been. You probably haven't heard of Turbo Modula-2 for CP... Read More

Turbo Pascal: A Great Choice For Programming Under CP/M

CP/M was blessed with many programming languages, each with their own strengths and weaknesses. I think that Turbo Pascal stands out from these and I'm not alone. When Turbo Pascal was released in 19... Read More

Floppy Days: A New Vintage Computing Podcast

#Podcast
#Retro

I have just finished listening to the first episode of Floppy Days and I'm pleased to report that it looks like this is going to be a good addition to the vintage computing landscape. The presenter, R... Read More

Dealing Sympathetically with Legacy Code

I have often noticed programmers getting worked up about the legacy code they are maintaining. I know it is annoying having to wade through poor code, or worrying about making changes for fear of unex... Read More

The National Museum of Computing at Bletchley Park

#Museum
#Retro

The National Museum of Computing is the UK's largest museum dedicated to computing. It is located on the Bletchley Park estate just south of Milton Keynes and is easy to get to by car, bus or train. ... Read More