Hot answers tagged

71

This only works with 2 drives on the same controller and cable. The floppy controller doesn't know when the disk (hardware) has been switched on the port (software), so a transfer command can be issued on the IBM formatted disk, but run on the Amiga disk. This answer comes from the documentation for the utility Disk2FDI. Here's an excerpt from docs\tech\...


67

The architecture of most "color computers" of the 70s-80s was very tightly built around the NTSC color video standard. Almost all of them had a 14.31818 MHz crystal. Note that this is four times the 3.579545 MHz frequency of the NTSC color standard, which was called a "color clock". They divided that crystal frequency to derive their actual clock ...


61

The limitation is based on saving precious space on the 8 KiB boot ROM for the Amiga 1000. Before the "Insert Workbench" graphic ever graced an original Amiga 1000 from 1985, a user would first have to get past the "Insert Kickstart" screen. Since the original Amiga 1000 lacked any Kickstart in ROM, this initial image had to be stored in the very limited ...


53

Low number of bit planes (few colors) and low resolution saves kickstart ROM space as stated in the other answer(s). Another reason for the simplicity of the picture could be the limitation of available drawing tools when the kickstart logo was created. Considering the following to really be a post by the original artist Sheryl Knowles, creation of such an ...


44

Looking at the actual code, the iconic KS1.x Workbench disk-hand image is technically drawn as vector art — except for the texts, which are bitmaps. The machine-language code uses a simple “program” — stored in an array — to draw the different parts of the diskette, hand, and the fingers, run-time. This “DSL” implements three commands: Draw a polyline. ...


40

The ones you list are all S.A.M, from what is now SoftVoice Inc. It was developed first for the Apple II, Lisa, Atari 8-bit machines and the Commodore 64; based on awareness of those versions, the company was contracted directly to supply the bundled speech generators for the Macintosh and Amiga. So they all sound the same because they are ports of the same ...


38

The differences between PC floppy drives and Amiga floppy drives are as follows: PC floppy drives normally answer to drive select 1 (DS1), internal Amiga drives answer to DS0 pin 34 on the connector is used for disk change on the PC, disk ready on the Amiga pin 2 on the connector is used for high-density detection on the PC, disk change on the Amiga So ...


37

Earlier revisions had some bugs (errata) but they still work fine and the problems can be worked around. For instance the MMULibs software checks the revision of the chip when the computer boots and disables some problematic features. Doing that has a slight hit on performance but it's probably not noticeable. The main reason why chips with revision 6 are so ...


36

While some lawyers do occasionally file lawsuits based mainly on their targets having "deep pockets", like Microsoft had, this is not generally successful. In order for a typical corporate lawsuit to gain any traction in the court, the plaintiff must provide sufficient "standing". In order to establish standing, Apple sought to convince the court that ...


35

Any accelerator for the Amiga work by disabling the CPU and taking over the complete bus system to become the bus master. To accomplish this, a low level signal must be applied by the accelerator to pin BR (Bus Request). The CPU will answer asserting pin BG (Bus Grant). After the accelerator receives this signal, it acknoledges it by asserting BGACK. When ...


34

What's lacking is mostly raw number-crunching ability. The MP3 format is relatively lightweight, and can be implemented using only fixed-point math (no FPU required), but it still takes a fair amount of computation to turn compressed frequency-domain data into uncompressed time-domain data that can be fed to a DAC. This IEEE article quotes a minimum ...


34

You should be able to use the Amiga hard drive directly on your Linux computer (provided it still has IDE support). Linux also understands AFFS (Amiga Fast File systems), at least once AFFS support is compiled into the kernel (from your "self customized" wording I would assume you know how to do that). Apparently, some Linux tools don't seem to understand ...


32

How exactly did early computers like the Amiga, Atari ST and Macintosh handle the mouse while also carrying out demanding tasks? This was achieved by simply not low level handling the mouse. The Atari ST for example had a 6301 based keyboard controller handling keyboard and mouse (or joystick). The mouse is a simple bus mouse type sending a pair of phase ...


31

If you include clones, home retro computers were sold far into the 90's, including the Milan (Atari ST compatible, 1997-1999) and various Amiga compatible machines. There were also lots of ZX Spectrum clones produced in East Europe until the late 90's. However, if it's just about systems supported by their original manufacturer, the answer is likely: Acorn. ...


31

It was an advantage because the IBM PC became an extensible computing platform. The most popular competitor to it previously was the Apple II, another open platform. The PC, as a platform, was popular to users because of the choices it enabled, as developers because of the foundations that it laid, and engineering firms because they could focus on what they ...


31

The "Amiga Client Software for Novell Netware v1.4" (official name) was created in 1992 by Oxxi. It is available as a set of six(6) floppy disk images most places where Amiga abandon-ware is found. For instance, it can be found in the TOSEC Amiga archive. Commodore Amiga [TOSEC v2012-04-10]/Applications/[ADF]/Commodore Amiga - Applications - [ADF] (TOSEC-...


30

The Amiga disk format stores 512 bytes per sector, 11 sectors per track (a track is one side of a cylinder), double sided (i. e. 2 tracks per cylinder) with 80 cylinders per disk, which makes 80 * 2 * 11 * 512 = 901120 bytes = 901.12 kB = 880 KiB raw block data. The IBM-PC format also stores 512 bytes per sector, but only 9 sectors per track (on a Double ...


30

The cheapest option is to use the composite output, so it's compatible with any monitor that supports composite but it's only black and white. Or if you have the A520 modulator (about $25 on eBay), you can get a color image through composite, RF (not recommended), or modify the A520 for S-Video. If your TV has a standard definition tuner, you may also be ...


30

There are a few reasons why multi-platform 3D games turned out to be no faster on the Amiga than on other 68000-based platforms without its blitter: The developers may have targetted the lowest common denominator system and not taken advantage of the blitter when they ported to the Amiga. Early games and poor conversions tended to be like this. A naive ...


29

The first change is to patch this code: 00fc0196 266E003E movea.l $3e(a6), a3 00fc019a B7FC00080000 cmpa.l #$80000, a3 00fc01a0 622C bhi.s $fc01ce.l 00fc01a2 B7FC00040000 cmpa.l #$40000, a3 00fc01a8 6524 bcs....


29

After some research, I found the hardware engineer that built the DCTV and we exchanged some messages where he explained the system. This is the unedited text: Wow, it has been a long time... I didn't really remember! Luckily I still have all the lab books and design notes from those days filed away. We used a technique that encoded the data on two ...


29

Memory protection. It's not that preemptive multi-tasking is expensive, or hard. It's not. It's easy. It costs (or can cost) essentially the same as cooperative multitasking. You have to save process state in both cases. But what was holding back the older systems was their early reliance on systems without inherent memory protection, and those legacies ...


29

I don’t know what the situation was like in the US in 1990, but in Europe computers were still unusual in homes then. In my high school in a fairly affluent area, around 10% of my classmates had a computer at home. Most of the people I knew with Amigas in the 90s bought them to play games on, and in that respect they were a far more interesting proposition ...


28

Ranger was to be the next generation Amiga, which the original West Coast Amiga engineers began working on in 1986-87, following the release of the Amiga 1000. Jay Miner improved the graphics chipset for Ranger to address the twin problems of chip (i.e. Graphics, Sound, DMA) RAM memory space and bandwidth in the Amiga 1000. The Original Amiga chipset (OCS) ...


28

TL;DR: What functionality or convenience is gained by having these offsets be negative values from the base address? It provided easy access to two lists that can be extended independently in future versions with a single pointer. The Long Read: A single pointer can only point a single memory location (yes, sound obvious, but stay with me). So at first ...


27

As far as I know, there's no authoritative source, and the information out there is probably not really accurate. I will answer this from an electrical engineering perspective, and because I have implemented some of these fixes myself. First a little note about timing fixes: The expression timing fixes is not really accurate, but comes from the observation ...


27

The [pre-AGA] Amiga: uses a planar frame buffer, stored in memory that is shared with the CPU (and which therefore reduces the CPU's speed); provides dual-playfield hardware scrolling, but the total bit fetch total per output byte doesn't stretch beyond six, so you end up with e.g. a 7 colour foreground and an eight colour background; provides 8 hardware ...


27

The Amiga 9-pin joystick port is compatible with: Atari 800/VCS joysticks and paddles; Atari ST joysticks; Commodore Vic-20, C64, C64GS and C128 joysticks; Commodore Amiga computer joysticks and joypads; and Amiga CD32 joypads. This table from Wikipedia's page on the Atari Joystick Port showing the pin assignments of various systems using a 9-pin input ...


26

On a PAL Amiga, a full line sweep translates to about 454 virtual Lores (Low Resolution) pixels. (64 µs duration of a horizontal line, 7.093790 MHz pixel clock, which is about 140.968 ns per pixel: 64 µs / 140.968 ns ≈ 454). I say virtual pixels because not all of those pixels are actually usable as there is the horizontal sync period of about 4 µs and the ...


26

The Amiga OCS was not exploited in the same way as the C64's VIC-II simply because the OCS was designed from the beginning to support rapidly changing video output modes. Unlike the C64, and most 8-bit machines, the Amiga's display coprocessor (the "Copper") existed to allow display mode updates to occur many times during the raster. For machines like the ...


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