December 23rd, 2014

Mike Willegal shares VCF repair/maintenance presentations

Mike Willegal is one of the most knowledgeable hardware hackers in the community. So when Mike shares his accumulated wisdom, it’s probably something you’ll want to snag for your own reference library. Check out Mike’s ‘Apple II Repair Tips‘ page and also his recent VCF presentations in PDF format.

General Troubleshooting
Apple II Maintenance

Good stuff!

December 22nd, 2014

Roger Wagner’s ‘Assembly Lines: The Complete Book’ re-released under Creative Commons

Announced by Chris Torrence via Usenet Comp.Sys.Apple2

Assembly Lines: The Complete Book is now available! The book contains all 33 of Roger Wagner’s articles from Softalk magazine, as well as appendices on the 6502 instruction set, zero-page memory usage, and a beginner’s guide to using the Merlin Assembler. The book is currently available for 40% off on, and will be available at Amazon in a few weeks. Note: Roger Wagner has released the book under a Creative Commons NonCommercial-ShareAlike license, and I’m currently working on the eBook version.

FYI, I uploaded disk images of the Assembly Lines programs to the Asimov website:

There are DOS and ProDOS versions. Disk1 contains the programs from chapters 1-17, while Disk2 contains the remaining chapters. Note that a few of the programs (in the DOS chapter) will only work in DOS, not ProDOS.

You can download a copy of the Merlin assembler for DOS at: v2.48 (DOS 3.3).dsk

And for ProDOS: v2.58 (ProDOS) Disk 1-2.dsk

Brief Table of Contents:

1. Apple’s Architecture
2. The Monitor
3. Assemblers
4. Loops and Counters
5. Loops, Branches, COUT, and Paddles
6. I/O Using Monitor and Keyboards
7. Addressing Modes
8. Sound Generation
9. The Stack
10. Addition and Subtraction
11. DOS and Disk Access
12. Shift Operators and Logical Operators
13. I/O Routines
14. Reading and Writing Files on Disk
15. Special Programming Techniques
16. Passing Data from Applesoft BASIC
17. More Applesoft Data Passing
18. Applesoft Hi-Res Graphics
19. Calling Hi-Res Graphics Routines
20. Structure of the Hi-Res Display Screen
21. Hi-Res Plotting in Assembly
22. Even Better Hi-Res Plotting
23. Hi-Res Graphics SCRN Function
24. The Collision Counter, DRAW, XDRAW
25. Explosions and Special Effects
26. Passing Floating-Point Data
27. Floating-Point Math Routines
28. The BCD, or Binary Coded Decimal
29. Intercepting Output
30. Intercepting Input
31. Hi-Res Character Generator
32. Hi-Res Character Editor
33. The 65C02
Appendix A: Contest
Appendix B: Assembly Commands
Appendix C: 6502 Instruction Set
Appendix D: Monitor Subroutines
Appendix E: ASCII and Screen Charts
Appendix F: Zero-Page Memory Usage
Appendix G: Beginner’s Guide to Merlin
List of Programs
Directory Listing for Program Disks
Quick Reference

September 19th, 2014

Introduction to Assembly Language Programming On the Apple IIGS – Lesson 1

September 6th, 2014

Dagen Brock’s ‘Introduction to Assembly Programming on the Apple IIgs’ – Lesson 0 Follow-up

August 2nd, 2014

Your new computer, it’s more than just an appliance you know…

March 28th, 2014

Tony Diaz posts video on swapping/repairing heads on Apple 3.5 drives

May 7th, 2013

Prince of Persia source code analyzed, documented

You may recall from our prior Prince of Persia coverage that Jason Scott and Tony Diaz helped Jordon Mechner resurrect the PoP source code from Mechner’s old disks and upload it to Github. Recently, Jason Scott posted a follow-up on Facebook’s Apple II Enthusiasts group about the efforts of PoP fan Adam Green.

Here’s Jason’s post:

Great news on the Prince of Persia front: Adam Green, a huge fan of the code and the original game, has been spending the time since Tony Diaz and I worked with Jordan Mechner put Prince of Persia on Github. He’s reverse engineered everything, documented it to within an inch of its life, and then created instructions and helper code to allow someone to actually build working images of Prince of Persia that boot in emulators (and possibly an Apple II). It’s a monumental achievement, and what we dreamed someone might have the time and effort to get done. If you scroll down, you can read all the essays he’s written explaining all the ways the code, the disk protection, and the system works. Great stuff.

You can see all Adam’s contributions here.

March 15th, 2013

David Schmenk’s QuickCam //e project gets documentation

Remember David Schmenk’s awesome hardware hack where he routed the output of an old parallel Connectix QuickCam to his Apple IIe through an Apple Parallel Card?  Of course you do.  Here’s how he did it, in case you want to build your own: Part I – The Hardware, Part II – The Software.

July 19th, 2012

Melissa Barron’s unique floppy disk sleeves

If you are subscribed to Juiced.GS, you’re one of the lucky people who received not only another issue of great Apple II content, but a 5.25″ floppy disk containing the recently-released Drift demos, as well.  The disks came in hand-made floppy jackets designed by Apple II artist Melissa Barron, and yesterday, she posted to her Tumblr a detailed walkthrough of her creation process.





July 8th, 2012

Easy 6502 assembly language ebook

Still haven’t learned how to program your Apple II in its native language?  Maybe this “tiny ebook” is just what you need to get started.  Author Nick Morgan writes:

In this tiny ebook I’m going to show you how to get started writing 6502 assembly language. The 6502 processor was massive in the seventies and eighties, powering famous computers like the BBC Micro, Atari 2600, Commodore 64, and the Nintendo Entertainment System. Bender in Futurama has a 6502 processor for a brain. Even the Terminator was programmed in 6502.

Check it out over at github now.

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