Questions tagged [amiga]

For questions related to the Commodore Amiga family of personal computers.

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17
votes
2answers
868 views

How to create a switchless multi-system 2 button Atari joystick?

All systems that use the Atari 9 pin joystick standard make use of the following pins in consistent ways, with each direction and the fire button being connected to the ground pin when pushed. 1 - up ...
16
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3answers
4k views

What happened to ZIP RAM?

I have several retro machines and add-on cards for the Amiga that use ZIP RAM. This vertically mounted chip design enjoyed a brief popularity in the early 1990s, in between the original DIP DRAM and ...
16
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2answers
2k views

Why do drives occupy memory on Amigas

I was reading this question, and it sparked an old memory. I had an Amiga 600 a long time ago. And I used to play Secrets of Monkey Island on it, great game. But then I upgraded the computer and ...
16
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1answer
2k views

How could Amiga computers play 14 bit sound?

The "Paula" chip used for sound output in all Amiga computers had 4 8bit sound channels (arguably comparable to 9bit stereo). There were programs/libraries which could play 14bit stereo on the Amiga ...
16
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4answers
1k views

Appropriate battery replacement for my A3000

I know the interwebs are full of information relating to the replacement of batteries for various computers, and the Amiga's are no different. But before I do anything rash, I wanted to ask for some ...
16
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2answers
3k views

Booting an Amiga 1000 directly to the hard drive without Kickstart floppy

The Amiga computers such as the Amiga 1000 required a Kickstart floppy to be able to boot directly into a hard drive. I have a Amiga 1000 as well but missing the Kickstart floppy. I would like to ...
16
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2answers
1k views

Creating a new locale.library language support for AmigaOS

Looking through the LO (localisation) disk for Workbench 3.1, I see that the language files are binary. I'd like to create a Gaeilge (Irish) localisation file. How is this done on Amiga? Update: ...
16
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1answer
559 views

Seeking details relating to Amiga 3000 serial numbers

I am the original owner of my Amiga 3000. As I remember it, I purchased the machine fairly early after release. I'm cleaning and detailing the machine, and I took a quick picture of the serial ...
15
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2answers
1k views

What information is encoded in the 22-digit barcodes on the Amiga's case?

What information is encoded in Amiga's 22-digit barcodes? For example: 0103791363642010121234
15
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1answer
854 views

What is the Kelly chip?

The Amiga 3000+ DevCon 1991 notes says: On the A3000+, these resources include the Amiga "Pandora" chip set (Alice, Lisa, Kelly, and Paula), However, a Kelly chip is not part of the official ...
15
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1answer
452 views

What does the H protection bit mean under classic AmigaOS?

The AmigaOS file protection bits allows for Read, Write, eXecute, Delete permissions on files, similarly to Unix (save for the Delete permission). Additional bits are Archive (reset when a file is ...
15
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4answers
7k views

How do I attach and use a CD-ROM drive to an Amiga?

I would like to add a CD-ROM drive to an Amiga. I have not tried this for several years and I remember things failing to work without giving any useful errors, multiple choices of device and ...
15
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1answer
853 views

How do Amiga "Monitor" drivers work?

A "Monitor" driver for an Amiga is a file which, when placed in DEVS:Monitors, enables additional screenmodes. The standard PAL or NTSC driver, which provides screenmodes compatible with consumer TV ...
14
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1answer
895 views

What is the relationship between Amiga audio and the MOD music file format?

What is the the MOD music file format? Exactly how does it relate to the Amiga 1000 audio hardware? Did the MOD format become popular on non-Amiga computers? If so, why?
14
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2answers
2k views

How would I reliably detect the amount of RAM, including Fast RAM?

If I was to write an Amiga game, what would be the best/most reliable way to detect how much RAM is actually available? Looking at Action's Guide to AGA-Fixing!, he mentions Faulty Memory Detection: ...
14
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2answers
2k views

What options were available for having an Amiga 1000 not be dependent on a KickStart disk?

I bought an Amiga 1000 second-hand many years ago for $50. In this deal I received a spare motherboard as the one installed in the chassis was upgraded; most notably, it had KickStart on ROM and thus ...
14
votes
1answer
945 views

Does the Commodore CDTV-CR contain a 65C02 for some reason?

Browsing around the FS-UAE source code I discovered a 65(S)C02 emulation core, which appears to not be referenced anywhere outside of some CDTV-CR related source file. Apparently, a CDTV is ...
14
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3answers
609 views

Who invented scrollable screens in Amiga?

A well known feature of Amiga is the ability to have multiple Intuition screens (ViewPorts in graphics.library parlance) that coexist and can be laid out on the screen so that they overlap vertically. ...
14
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2answers
636 views

What is the minimum set of Kickstart kernel modules to allow an Amiga to boot?

Amiga OS resident modules (libraries, devices, etc...) are location-agnostic, in that it is technically possible to compile them as location-independent code to be loaded at runtime from disk, or to ...
14
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2answers
770 views

Can I trigger the Amiga ROM debugger from the boot prompt?

Suppose I have an Amiga computer without any working boot disks. Is it possible to trigger the built-in ROM monitor (RomWack or SAD, see https://theamigamuseum.com/amiga-kickstart-workbench-os/guru-...
13
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4answers
4k views

Amiga 500 OCS/ECS vs Mega Drive VDP

Superficially the Amiga 500 and Mega Drive are similar. Both run a Motorola 68000 CPU at similar clocks and both have dedicated hardware for sprite and other graphics operations. Comparing the arcade ...
13
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2answers
2k views

Should I use the internal or external drive for loading Amiga 500 games?

I have a working (I think) Amiga 500 system with an internal DF0 drive and an external DF1 drive. The Amiga 500 powers up with Workbench v1.3. Can anyone tell me how to access a game disc (Marble ...
13
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3answers
1k views

Is there a seamless, Wine-like AmigaOS emulator for Linux, specifically for text-based programs?

After trying out FS-UAE on my Fedora Linux system, which worked quite nicely, I got to thinking. Even though when the Amiga was originally released in the middle 1980s, it was revolutionary in its ...
13
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6answers
1k views

Amiga floppy disks and GCR vs MFM

According to the Wikipedia article on GCR, the Commodore 1541 disk drive used a particularly efficient GCR encoding scheme to cram 170K onto the same 5.25" disks that in an Apple drive only ...
13
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2answers
1k views

Why did Commodore not upgrade OCS straightforwardly to 32-bit architecture?

This is somewhat of a speculative question... Amiga's 1985 Original Chip Set is inherently a 16bit architecture (the data bus is 16bit, registers are 16bit, the blitter itself is 16 state machines ...
13
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3answers
4k views

Extended ROMs on the Amiga CD32 and CDTV

Continuing my series of questions about Amiga ROMs :-) The Commodore CDTV contained a normal Kickstart 1.3 ROM, plus an "extended ROM". From http://www.l8r.net/technical/cdtv-technical.html: The ...
13
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3answers
952 views

Why was OCS low resolution limited to 6 bitplanes?

I'm looking for information whether there has ever been an official statement by Commodore back in the days on why the Original Chipset was limited to doing 6 bitplanes only when running in low ...
13
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5answers
395 views

Preventing socketed chip corrosion?

I spent a couple hours repairing an Amiga A3000 that wouldn't boot yesterday. The fix was to remove Kickstart ROMs, clean the DIP leads and sockets with contact cleaner, and re-insert. Apparently a ...
13
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3answers
5k views

What is the benefit of increasing Amiga chip memory?

For example, an Amiga 500+ has 1MiB of chip memory, but it can be expanded to 2MiB. What would be the advantage?
13
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3answers
2k views

Was there ever a Kickstart that took advantage of 68020+ instructions that would work on an A2000?

Back in the day with my A2500/30, I always wanted to get the 68030 versions of software if I could because presumably I'd be able to get a few percentage more performance in some cases. However, I get ...
13
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2answers
708 views

What are all the fixed addresses of AmigaOS?

I was reading Richard Downer's excellent response about how Amiga libraries work and one sentence in particular got my attention: Yes, a pointer to exec.library is always at $4, and this is (in ...
13
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3answers
2k views

Is the metal shielding required in all-in-one Amiga models?

All-in-one Amiga computers (500, 600, 1200) have metal shielding surrounding the mainboard. It is in two parts, one below the mainboard and one on top. The mainboard is physically linked to the lower ...
13
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2answers
870 views

Protected/virtual memory support in classic AmigaOS

It is a well-known fact that AmigaOS is a single address space, totally unprotected memory operating system. The original implementation ran on a Motorola 68000, that did not support virtual memory if ...
13
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1answer
592 views

What does Personal Paint documentation actually refer to by "unmaskable interrupt" for its "crash protection feature"?

Personal Paint was a gfx program for Amiga that introduced many novel concepts, some quite ingenious, some... controversial. Among all, it had a "crash protection" feature, that was meant to enable ...
13
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1answer
2k views

Practical differences between the three Amiga 500 rev 5 motherboards?

The Big Book of Amiga Hardware lists three different versions of the Amiga 500 rev 5 motherboard which it names Type 1, Type 2, and Type 3. Were the changes made only to simplify manufacturing, or ...
13
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2answers
2k views

What exactly are the differences between Kickstart 1.2 and 1.3?

The only very known difference is that Kickstart 1.3 fixes the silly bug that prevented Kickstart 1.2 to boot from a hard disk (a routine in the boot code uses A6 loaded with an incorrect library base,...
13
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3answers
814 views

What interface did Video Backup System use?

I remember the Video Backup System for Amiga advertized in Polish computer magazines of late 90s, "store hundreds of diskettes on a single VHS tape!" I seriously considered buying it (and a ...
12
votes
2answers
644 views

What did disk-validator do?

...besides relabelling the disk to 'Lazarus' and helping the Saddam virus spread? I know it was supposed to 'fix' corrupted disks that were ejected during a write operation. I don't think I've seen a ...
12
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3answers
660 views

Will using a clockport RTC card on an Amiga 1200 clash with the RTC on an accelerator card?

I have an accelerator card fitted to my Amiga 1200. The accelerator includes a real-time clock, but I noticed that the soldered-on rechargeable battery was in danger of leaking, so I cut it off before ...
12
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1answer
344 views

Amiga A1050 schematic

I’m trying to resurrect a Craigslist Amiga A1000. After replacing Paula it now boots. Several basics still missing (RF shields, screws, port covers, etc.) but essential electronics are okay. However, ...
12
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2answers
1k views

Replacing the floppy drives in my Amiga 3000

My Amiga 3000 is starting to show its age, and recently one of the two internal floppy disk drives appears to have given up the ghost... I'd like to replace the drive but the A3000 case doesn't have ...
12
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2answers
1k views

What was the A1200 Flash ROM support meant for?

Question inspired by this answer's last paragraph: https://retrocomputing.stackexchange.com/a/1307/2155 The Revision 1 A1200 schematics show that the system originally had support for a two internal ...
12
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2answers
858 views

How are Amiga Kickstart Relocation Files (.RTB) created?

Examples of Amiga Kickstart files (ROMs) can be 256k (1.2/1.3) or 512k (3.0/3.1) binary files, located at $FC0000-$1000000 or $F80000-$1000000 Several programs are able to "soft-kick" Amigas, i.e. ...
12
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2answers
1k views

How does the Amiga chipset RGA bus work?

The RGA bus is the bus that connects Agnus/Alice with Denise/Lisa and Paula. What is it used for? I guess at a minimum to write/read registers in Denise/Lisa and Paula, and I guess to feed data to ...
12
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2answers
1k views

Why was Windows 3.1 so dreadfully slow on an Amiga A2286 bridgeboard?

Back in the day I had an Amiga 2500/30 with an A2286 as my "swiss army knife" home computer; not only did I have the ability to run MacOS (ShapeShifter) at native speed, but the 8MHz 286 bridgeboard ...
12
votes
1answer
894 views

How did the Amiga 1000 WCS (write controlled store) for Kickstart work?

Most Amiga computers have Kickstart (the core of the operating system) on ROM. But the original Amiga 1000 instead loaded Kickstart from disk. It had boot ROM that would run some self tests and then ...
11
votes
4answers
1k views

What graphics sytems used display lists?

As near as I can tell, there seems to have been roughly speaking two schools of thought when it comes to graphics hardware among early consoles, what I will call the Atari and Texas Instruments ...
11
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2answers
558 views

Amiga Video Toaster support

What features of the Amiga chipset architecture and/or Amiga OS made it possible to design the Video Toaster for the Amiga? Why weren't there similar (cost-effective) video products for the PC or Mac?...
11
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3answers
3k views

What advantages are there to replacing Kickstart 3.0 with Kickstart 3.1?

I have an Amiga that has the Kickstart 3.0 ROMs installed. What advantages are there to replacing the Kickstart ROMs with 3.1? Is there any software that requires Kickstart 3.1 to function?
11
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3answers
1k views

Set keyboard layout in Amiga Workbench 3.1

I did a fresh install of the Cloanto amiga-os-310-install.adf disk to a hard drive, and then I wanted to change the keyboard layout to Swedish. I tried SYS:System/SetMap s but then I've learned that ...