Search found 1546 matches

by BigEd
Mon Jan 15, 2018 9:12 am
Forum: off-topic
Topic: How many people found computer self-assembly annoying?
Replies: 10
Views: 303

Re: How many people found computer self-assembly annoying?

First soldering I did was assembling my first computer - I think that means I was not a keen electronics hobbyist, I was someone who very much wanted a computer and could barely afford one. (Second soldering I did was to rework every joint, at which point the thing worked.) Not only did selling a ki...
by BigEd
Sun Jan 14, 2018 8:06 am
Forum: programming
Topic: Filing system testing, BASIC, line numbers and version control
Replies: 9
Views: 176

Re: Filing system testing, BASIC, line numbers and version control

Does ON ERROR PROChandler : ENDProc do the job? Or ON ERROR PROChandler : RETURN which is to say, each test would be encapsulated in a procedure or a subroutine, and the idea is to deal with the error and then bale out so the next test can run. [Edit: no, it doesn't, as an error loses all nesting st...
by BigEd
Sat Jan 13, 2018 6:14 pm
Forum: hardware
Topic: SpectROM - Speccy emulator for the Pi co-pro
Replies: 35
Views: 889

Re: SpectROM - Speccy emulator for the Pi co-pro

Would I be right in thinking that the 256-byte transfer could be useful, providing it's not too tacky or inefficient to pad updates into 256 byte blocks? (The data could still be compressed or encoded, but a 257 byte update or a 1 byte update would be rather inefficient.) [Edit: I see now the sugges...
by BigEd
Sat Jan 13, 2018 2:44 pm
Forum: hardware
Topic: DIY cheap pitubedirect signal converter building
Replies: 4
Views: 157

Re: DIY cheap pitubedirect signal converter building

€10 all-in, and it works? Excellent!
by BigEd
Sat Jan 13, 2018 2:40 pm
Forum: hardware
Topic: SpectROM - Speccy emulator for the Pi co-pro
Replies: 35
Views: 889

Re: SpectROM - Speccy emulator for the Pi co-pro

Looking again at Dave's host-side VDU handler, I see that it doesn't mess about - and the data transferred is not zero-terminated as I said, it's (up to) a screen's worth of updates where each block of pixel updates is zero-terminated. So, it's compressed fairly well, and uncompressed directly into ...
by BigEd
Sat Jan 13, 2018 1:02 pm
Forum: hardware
Topic: SpectROM - Speccy emulator for the Pi co-pro
Replies: 35
Views: 889

Re: SpectROM - Speccy emulator for the Pi co-pro

As the copro runs ridiculously fast, overhead on that side of the Tube mightn't amount to much - I'd guess overhead on the host side is the case to worry about. But it might well be better to experiment than to theorise...

This is an excellent new development though!
by BigEd
Sat Jan 13, 2018 10:00 am
Forum: hardware
Topic: SpectROM - Speccy emulator for the Pi co-pro
Replies: 35
Views: 889

Re: SpectROM - Speccy emulator for the Pi co-pro

Is the Pi fast enough to look for small areas of shifted/scrolled graphics and send a scroll command for an area? Also, I'm using some bespoke OSWORD routines to pass the data as I don't think there's a way to access the Tube registers directly from the native Pi co-pro. Adding a couple of SWIs to ...
by BigEd
Thu Jan 11, 2018 6:01 am
Forum: hardware
Topic: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)
Replies: 1018
Views: 78983

Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)

(I see PiTubeDirect has been posted on Hacker News (again))
by BigEd
Wed Jan 10, 2018 12:08 pm
Forum: off-topic
Topic: online study?
Replies: 25
Views: 722

Re: online study?

By coincidence and for future reference, this discussion highlights some online courses, or resources: - https://github.com/ossu/computer-science - https://teachyourselfcs.com/ - https://functionalcs.github.io/curriculum/ and this accredited degree course: - https://www.uopeople.edu/programs/cs/degr...
by BigEd
Wed Jan 10, 2018 9:49 am
Forum: programming
Topic: 32k memory management for dummies
Replies: 28
Views: 737

Re: 32k memory management for dummies

(Not to worry, BBC Basic's floating point is OK with halving and numbers ending in .5)
by BigEd
Tue Jan 09, 2018 6:48 pm
Forum: off-topic
Topic: online study?
Replies: 25
Views: 722

Re: online study?

At first glance, these would be hard for someone who struggled with A level maths. The questions are testing your understanding and your problem solving ability, not your memory or your pattern-matching skills. And that's a good thing - if you get into an undergraduate course which isn't suitable fo...
by BigEd
Sun Jan 07, 2018 7:48 pm
Forum: off-topic
Topic: disk images: graphical images of data layout on disk
Replies: 1
Views: 104

disk images: graphical images of data layout on disk

An interesting series of tweets from Paul Rickards, visualising some C64 disks.
by BigEd
Fri Jan 05, 2018 8:04 pm
Forum: other vintage computer hardware, software and games
Topic: 34C3: Ultimate Apollo Guidance Computer Talk
Replies: 3
Views: 134

Re: 34C3: Ultimate Apollo Guidance Computer Talk

I'm half way through - I needed to pause for breath!
(It's on YouTube too.)
The AGC is a remarkable machine, with some interesting quirks.
by BigEd
Fri Jan 05, 2018 4:38 pm
Forum: hardware
Topic: Electron cassette counter revolution rate
Replies: 26
Views: 549

Re: Electron cassette counter revolution rate

(Eyeballing this image , I'd say the rate of counting could vary about 1:2.5 between a full spool and an empty one, on a C60. However, a C15 would have a much smaller ratio.) As Acorn sold their own brand of data recorder (the ANF03 ), that would be a good one to get a calibration from. (Crossed in ...
by BigEd
Fri Jan 05, 2018 11:36 am
Forum: off-topic
Topic: just a question for uk :)
Replies: 5
Views: 175

Re: just a question for uk :)

We had some bees in a chimney. The bee man put some kind of smoke bomb in (having tried something more bee-preserving first). But the bees were in the next chimney over... anyway, they've gone now, one way or another.

I'm sure the Bristol smoke is applicable for all EU purposes.
by BigEd
Fri Jan 05, 2018 10:17 am
Forum: off-topic
Topic: just a question for uk :)
Replies: 5
Views: 175

Re: just a question for uk :)

Bristol's a very nice place! Very diverse too, so there will be industrial parts where the smoke pellets are made, and leafy suburbs for people who can afford to live in them, and everything in between. These days it's something of an aerospace hub, also microelectronics, and two well-regarded unive...
by BigEd
Thu Jan 04, 2018 7:32 pm
Forum: other vintage computer hardware, software and games
Topic: Early 70s Calculators
Replies: 43
Views: 2401

Re: Early 70s Calculators

Very nice! That looks rather like a Rockwell logo on the chips, which is interesting. I wonder if NEC and Hitachi were up to speed at that time. I was lucky enough to get a 72 or 73 calculator as a present - the Sperry Remington 661D, a six-digit wonder. (Same design as the Casio Mini CM-602, so I'd...
by BigEd
Tue Jan 02, 2018 10:17 pm
Forum: programming
Topic: C Compiler and % in filenames
Replies: 8
Views: 240

Re: C Compiler and % in filenames

(See also this thread and this one.)
by BigEd
Tue Jan 02, 2018 10:15 pm
Forum: programming
Topic: C Compiler and % in filenames
Replies: 8
Views: 240

Re: C Compiler and % in filenames

cc65 is still actively developed - the link on mdfs.net is to the previous maintainer's notice of quitting. See here instead:
https://github.com/cc65/cc65

Another collection of pointers can be found here:
http://6502.org/tools/lang/
by BigEd
Tue Jan 02, 2018 10:40 am
Forum: general
Topic: Don't have a desolder station or hot air gun!
Replies: 17
Views: 415

Re: Don't have a desolder station or hot air gun!

Yes, I'd agree that it's the IR, not the visible or the UV, which is most important here.
by BigEd
Tue Jan 02, 2018 7:52 am
Forum: general
Topic: Don't have a desolder station or hot air gun!
Replies: 17
Views: 415

Re: Don't have a desolder station or hot air gun!

I think the car headlight halogen has two advantages over any ordinary 100w bulb: it's halogen, so the filament is hotter, so there's more infra red than from an ordinary filament; it has a metal reflector so you get the heat from the back of the filament too. An ordinary domestic halogen has a dich...
by BigEd
Tue Jan 02, 2018 7:46 am
Forum: hardware
Topic: input latency of BBC Micro? (keypress to mode 7 update)
Replies: 2
Views: 202

Re: input latency of BBC Micro? (keypress to mode 7 update)

My camera has a 100fps movie mode, but it sounds like that's not fast enough in this case.
by BigEd
Mon Jan 01, 2018 5:46 pm
Forum: hardware
Topic: input latency of BBC Micro? (keypress to mode 7 update)
Replies: 2
Views: 202

input latency of BBC Micro? (keypress to mode 7 update)

Anyone an idea of how long it takes a Beeb to process a keystroke?

(This article is all about input latency and how the Apple II is much better than a modern PC, and I wondered how the Beeb compares.)
by BigEd
Sat Dec 30, 2017 2:58 pm
Forum: hardware
Topic: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)
Replies: 1018
Views: 78983

Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)

Well done Dave! Revaldinho has been working on a BCPL compiler targeting the OPC6 and 7 - these are a 16 and a 32 bit version of a small simple CPU - and there are a couple of threads worth reading if you like this sort of thing: ⋅  BCPL (and Enigma) on OPC6 ⋅  OPC7 - a 32 bit ma...
by BigEd
Fri Dec 29, 2017 12:14 pm
Forum: off-topic
Topic: mdfs.net offline
Replies: 14
Views: 803

Re: mdfs.net offline

Some info here about the present and the previous status of the domain:
https://www.domainhistory.net/mdfs.net
by BigEd
Thu Dec 28, 2017 11:12 pm
Forum: hardware
Topic: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)
Replies: 1018
Views: 78983

Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)

About max latency: see previously (upthread).

About the ARM Basics: yes they have ARM assemblers built in. For the native ARM, you need BAS135. I'm sure there's an SSD around somewhere nearby. (Edit: see here)
by BigEd
Wed Dec 27, 2017 9:54 pm
Forum: off-topic
Topic: Sophie Wilson on TV
Replies: 4
Views: 458

Re: Sophie Wilson on TV

Thanks for that - can view it here. I was pleased to get the maths one right... couldn't get anything else.

Edit: from Sophie's intro, the ARM1:
Sophie-ARM1.png
by BigEd
Wed Dec 27, 2017 10:49 am
Forum: software & utilities for the pc, mac or unix
Topic: How to convert tape to UEF
Replies: 34
Views: 878

Re: How to convert tape to UEF

pau1ie wrote:...I tried splicing block 19 from the recording where it worked...

Could you share this other recording? Perhaps it can still be successfully spliced.
by BigEd
Sun Dec 24, 2017 10:32 pm
Forum: software & utilities for the pc, mac or unix
Topic: How to convert tape to UEF
Replies: 34
Views: 878

Re: How to convert tape to UEF

Here's a screenshot of four data blocks, in between five solid tones. There's a bit of a tape dropout in the middle of the fourth block, about 11.7 sec timestamp - you can see the high and low tone bars both vanish. It is easier to see the dropout by looking at the 'waveform db' view, but easier to ...
by BigEd
Sun Dec 24, 2017 10:28 pm
Forum: software & utilities for the pc, mac or unix
Topic: How to convert tape to UEF
Replies: 34
Views: 878

Re: How to convert tape to UEF

(No, cancel that: stay with linear. Perhaps change the max frequency to 4000. What you see is one solid horizontal bar for the inter-block tone, and then the data blocks are more of a mush but with two horizontal bars broadly visible.)

Go to advanced search