Some Assembly Required
geoWrite is a WYSIWYG rich text editor for the Commodore 64 GEOS operating system. I created a reverse-engineered source version of the geoWrite 2.1 for the C64 (English and German) for the cc65 compiler suite:
In the series about the internals of the geoWrite WYSIWYG text editor for the C64, this article discusses how the app consolidates keyboard input to keep up with fast typists.
In the series about the internals of the geoWrite WYSIWYG text editor for the C64, this article discusses its efficient cross-application cut/copy/paste implementation.
In the series about the internals of the geoWrite WYSIWYG text editor for the C64, this article discusses how its file format allows the app to efficiently edit documents hundreds of KB in size.
In the series about the internals of the geoWrite WYSIWYG text editor for the C64, this article discusses what was required for the German localization.
In the series about the internals of the geoWrite WYSIWYG text editor for the C64, this article discusses the geoWrite copy protection.
In the series about the internals of the geoWrite WYSIWYG text editor for the C64, this article discusses how it makes maximum use of the scarce zero page space.
In the series about the internals of the geoWrite WYSIWYG text editor for the C64, this article discusses the font manager’s system of caches for pixel fonts.
In the series about the internals of the geoWrite WYSIWYG text editor for the C64, this article discusses how the app manages to extend its usable RAM by 5 KB using a custom screen recovery solution.
geoWrite is a WYSIWYG rich text editor for the Commodore 64 GEOS operating system, which runs with a total of just 64 KB of RAM. In the series about the internals of geoWrite, this article discusses how it manages to fit 52 KB of code into the available 23 KB of application RAM.
All disk drives connected to the Serial Bus of a Commodore 64 speak the Commodore DOS protocol, from the popular 1541 5.25″ drive to the modern sd2iec SD card interfaces. CMDR-DOS is a new and open source implementation of the Commodore DOS protocol, using SD cards with the FAT32 filesystem and supporting advances features like partitions, subdirectories and timestamps – and running on a 65c02!
We are presenting the (to our knowledge) first full-featured open source library for 65c02 CPUs for accessing FAT32 formatted disks.
In this episode of computer archeology, we deconstruct a very interesting case of borrowing code from multiple places – but first try this D64 disk image with any Commodore 64 emulator or a real C64:
Feiler, Jesse.
Rhapsody Developer’s Guide.
Boston: AP Professional, 1997.
ISBN 0-12-251334-7
(528 pages, 13.3 MB PDF)
(Read comments for solution.)
If you try to set the clock in Lisa OS 3.1 to 2010, you’re out of luck:
A while ago, I complained about operating systems with overly complicated startup code that spends too much time in assembly and does hot have printf() or framebuffer access until very late.
In many operating systems, I have seen overly complicated startup code. Too much is done in assembly, and printf() and framebuffer access is only available very late. In the next three blog posts, I will show how this can be avoided.
The Copland project was Apple’s ill-fated attempt in the mid 1990s to replace the aging classic Mac OS with a more modern operating system that had a microkernel, virtual memory and preemptive multitasking. Information on Copland is scarce, therefore I have compiled 20 hard to find Copland reference documents, as well as the 359 page book “Mac OS 8 Revealed”.
The Apple Lisa from 1983 was the first consumer-class computer with a graphical user interface and significantly more advanced than the 1984 Macintosh, which had a similar UI, but a comparatively primitive underlying OS. Here, I present a searchable PDF of the rare “Operating System Reference Manual for the Lisa” (1983), as well as a quick overview of the OS and how it compares to UNIX.