Questions tagged [amstrad]

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8 votes
1 answer
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How big is the screen of the Amstrad CPC 464?

The Amstrad CPC 464, released in 1984, was distinctive for, among other things, being the first UK home computer to have a built-in monitor instead of assuming you would use a TV set. How big was the ...
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12 votes
2 answers
2k views

Did early versions of DR-DOS preserve more registers than MS-DOS?

The early Amstrad IBM compatible PC the PC1512 initially included DR-DOS, according to its page at Old-Computers.com: It was sold with MS-DOS 3.2, DR-DOS plus 1.2 (an operating system from Digital ...
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6 votes
3 answers
1k views

How long are interrupt requests remembered on the Amstrad CPC?

I'm trying to emulate an Amstrad CPC 464. Currently, I'm working on interrupt handling and I'm wondering: Some Z80 instructions, like EI or decoding multiple consecutive 0xdd prefixes don't accept ...
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3 votes
2 answers
180 views

How can I format a higher capacity 3 inch disc on a regular CPC6128?

A standard Amstrad 3 inch disc can be formatted to CP/M Data format on the machine: single sided, single track, 40 tracks, 9 sectors/track, 512-byte sectors, no reserved tracks, 1k blocks, 2 directory ...
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1 vote
1 answer
162 views

Amstrad CPC 6128 - Key cap spring missing

Of course the unthinkable happened and I lost one cap key spring while cleaning the keyboard. I am still searching but assuming all things went south, what would be the best solution to replace them? ...
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4 votes
1 answer
203 views

Amstrad CPC 6128 - Bench Power Supply Connection Setup

I am definitely at the very beginning of my refurb-journey and learning every step now on the way ... I struggle with the following: I saw a video by Noel's Retrolab where he troubleshooted a CPC. He ...
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2 votes
3 answers
493 views

First time using an Amstrad CPC 6128 Disc Drive [duplicate]

I recently got my first Amstrad CPC and started refurbishing it. Now I wonder, I saw a video, on someone using the RPM test tool for the Amstrad. I found the download online, but this question might ...
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9 votes
1 answer
332 views

Trying to create a filesystem ROM for Amstrad CPC but tape is still waiting

Some background: I want to create a CPC MicroSD interface, so my first step is trying to hook the CAS* jumpblock entries just like AMSDOS and other DOSes do. My first goal is to override CAS CATALOG ...
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  • 251
6 votes
3 answers
501 views

Who produced all-in-one / wedge style IBM compatibles?

The RetroManCave YouTube channel recently made me aware of the Sinclair PC-200 / Amstrad PC-20 and I already knew about the Tandy 1000EX / 1000HX but were there any other IBM-compatibles (or mostly ...
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  • 391
11 votes
2 answers
280 views

Which addresses does the Motorola 6845 CRTC output during retrace?

I'm trying to understand how the video hardware (CRTC and Gate Array) in Amstrad CPCs works. Specifically, I have a question about the behavior of the refresh memory addresses and row adresses output ...
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  • 497
5 votes
1 answer
326 views

Are all 64k x 4-bit ICs interchangeable for Amstrad-era ZX Spectrum 128k +2/+3?

There were 4 64k x 4-bit Integrated Circuit chips in the Amstrad-era Sinclair ZX Spectrum +2 and +3 models. These are known as the +2A, +2B (both +2 "black"), +3 and +3B (also both black cases). I ...
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  • 403
3 votes
5 answers
484 views

How to determine where in RAM the current Basic program resides on Amstrad microcomputers?

How can I find where in memory to locate the current Basic program in an Amstrad CPC/PCW family Zilog Z80-based microcomputer? Is it always the same address? A different well-known address depending ...
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3 votes
2 answers
146 views

Is there a "most correct" name for the disk format / filesystem used by Amstrads and Spectrum +3's?

The native floppy disk format/layout or "filesystem" used by Amstrad microcomputers such as the CPC and PCW range and by the Sinclair Spectrum +3 are versions of one that came from CP/M. In Amstrad ...
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2 votes
1 answer
170 views

Are there open source Java libraries for reading DSK and EDSK disk image files as used by Amstrad and Spectrum +3 emulators?

I've been working on some modules for the Ghidra reverse engineering tool. Ghidra is written in Java, which I'd always avoided when I was more actively programming so this is an opportunity to learn ...
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4 votes
1 answer
343 views

What did "double track" mean in relation to floppy disks?

I mostly used 3½″ floppies back in the day but I also used 5¼″ floppies to some extent on Apple II's and TRS-80's. I was never exposed to 3″ floppy disks as used mainly on Amstrad microcomputers and ...
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