Search found 267 matches

by arg
Tue Jul 27, 2021 8:29 am
Forum: 8-bit acorn hardware
Topic: BeebSID circuit....
Replies: 8
Views: 263

Re: BeebSID circuit....

That schematic is misleadingly drawn though: LS02 is a NOR gate but drawn as a NAND.
by arg
Sat Jul 17, 2021 1:37 pm
Forum: 8-bit acorn hardware
Topic: Strange BBC Micro Issue 3 motherboard addition
Replies: 8
Views: 433

Re: Strange BBC Micro Issue 3 motherboard addition

I believe this was a factory mod in the early days of trying to make the Ferranti VIDPROC ULAs work satisfactorily.

Certainly my machine has it, and I'm pretty sure I didn't fit it myself; I remember seeing it on quite a few machines though I am not sure exactly when.
by arg
Fri Jul 16, 2021 9:07 am
Forum: 8-bit acorn hardware
Topic: Industrial use of 8bit kit
Replies: 27
Views: 742

Re: Industrial use of 8bit kit

BITD, one of our clients was an outfit called Maritime Dynamics, based somewhere near Cardiff. Interesting -- I'm almost in Cardiff and know someone in the University who might be able to help with this. A bit more digging reveals the company, and the precise location (Llantrisant): https://company...
by arg
Thu Jul 15, 2021 7:54 pm
Forum: 8-bit acorn hardware
Topic: Industrial use of 8bit kit
Replies: 27
Views: 742

Re: Industrial use of 8bit kit

Another one in the TV business was Autocue Ltd.

No prize for guessing what their product did, but it was BBC based with ordinary BBCs used to create the content on Econet fileservers, then specially modified BBC-derived hardware playing out the script to the presenters.
by arg
Thu Jul 15, 2021 2:58 pm
Forum: 8-bit acorn hardware
Topic: Industrial use of 8bit kit
Replies: 27
Views: 742

Re: Industrial use of 8bit kit

BITD, one of our clients was an outfit called Maritime Dynamics, based somewhere near Cardiff. They built ship simulators for training crews on supertankers and the like (equivalent of aircraft simulators, but everything goes at much slower speed!). The setup was initially multiple BBC micros on Eco...
by arg
Tue Jul 13, 2021 11:18 am
Forum: 8-bit acorn hardware
Topic: FileStore restoration
Replies: 134
Views: 4520

Re: FileStore restoration

Slightly interestingly the other disk interface board that I have, which appears to be an older one (issue D) doesn't seem to have any connection to pin 34 at all. I wonder why Acorn added that on the later one. Attempt to provide TERMPWR but picked the wrong pin? Do either of them have TERMPWR on ...
by arg
Tue Jul 13, 2021 10:10 am
Forum: 8-bit acorn hardware
Topic: The Beeb's cassette storage input circuit
Replies: 120
Views: 3108

Re: The Beeb's cassette storage input circuit

Where the effort was concentrated was reliability and functionality rather than speed, e.g. the ability to rewind and retry after an error, or reading sequential data tapes with motor control. They may seem trivial now but I think such features were uncommon on tape interfaces at the time. Yes, the...
by arg
Tue Jul 13, 2021 7:26 am
Forum: 8-bit acorn hardware
Topic: The Beeb's cassette storage input circuit
Replies: 120
Views: 3108

Re: The Beeb's cassette storage input circuit

I think that’s the whole point of that particular piece of work- take out all the margin allowed in the original design to allow for the variability of tape and instead spend it on higher throughput assuming perfectly timed input. More interesting BITD would have been 2400 (though there’s no way to ...
by arg
Fri Jul 09, 2021 9:29 pm
Forum: stardot FORUM
Topic: What controls forum login timeout?
Replies: 26
Views: 362

Re: What controls forum login timeout?

Fair enough
by arg
Fri Jul 09, 2021 8:14 pm
Forum: stardot FORUM
Topic: What controls forum login timeout?
Replies: 26
Views: 362

Re: What controls forum login timeout?

Yes, it seems very simple and the reason I posted in the first place was because I hoped that there was an obvious answer I missed. So thanks to those who pointed it out and apologies for the detour through wierd & wonderful theories before we got there. Is that wording hard-wired in PHPBB or is...
by arg
Fri Jul 09, 2021 4:12 pm
Forum: stardot FORUM
Topic: What controls forum login timeout?
Replies: 26
Views: 362

Re: What controls forum login timeout?

Where the log on details are auto filled, it’s best to select the remember me button first :wink: iOS by default doesn’t give you the option- it goes straight into the fingerprint-to-unlock-credentials as soon as the page loads (effectively a modal dialogue), and if you say ‘yes’ it fills in and su...
by arg
Fri Jul 09, 2021 3:46 pm
Forum: stardot FORUM
Topic: What controls forum login timeout?
Replies: 26
Views: 362

Re: What controls forum login timeout?

Right now I am enjoying the wonders of NHS WiFi (which admittedly was good enough on Wednesday night to watch the football all the way through without getting disconnected). My IP is currently 192.168.61.121 and I will see if it has changed next time I get logged out). 192.168 is your local network...
by arg
Fri Jul 09, 2021 2:07 pm
Forum: stardot FORUM
Topic: What controls forum login timeout?
Replies: 26
Views: 362

Re: What controls forum login timeout?

Ah ok that’s probably the whole problem! I assumed that was just the usual remember-the-userid-in-a-cookie thing. I did try pressing it once or twice, but usually use the browser’s form-filler that submits the form without giving you the chance to select options.

I will test and report back.
by arg
Fri Jul 09, 2021 1:28 pm
Forum: stardot FORUM
Topic: What controls forum login timeout?
Replies: 26
Views: 362

Re: What controls forum login timeout?

Newer versions of iOS (I think 14+) provide random MAC addresses for WiFi connections - called Private Address - designed to prevent someone tracking your device based on its static MAC address. This could be causing your iPhone to be assigned many different IP addresses, especially if wifi keeps d...
by arg
Fri Jul 09, 2021 1:21 pm
Forum: stardot FORUM
Topic: What controls forum login timeout?
Replies: 26
Views: 362

Re: What controls forum login timeout?

You are clicking the "stay logged in" button when you login? Without that you'll get a temporary session, and it's easy to miss! Hmm, I see no such button?? stardot.org.uk - User Control Panel - Login.png You don't have any cookie cleaner or similar tool loaded? Nope. Standard iOS browser...
by arg
Fri Jul 09, 2021 12:11 pm
Forum: stardot FORUM
Topic: What controls forum login timeout?
Replies: 26
Views: 362

Re: What controls forum login timeout?

No, the IPs are statically assigned (DHCP with fixed assignments).

I am less interested in fixing this on the laptop as the machine itself is clearly broken, but it possibly provides clues.

But the iPhone really ought to work. When I am home again I will try to log some traffic.
by arg
Fri Jul 09, 2021 10:27 am
Forum: stardot FORUM
Topic: What controls forum login timeout?
Replies: 26
Views: 362

Re: What controls forum login timeout?

Ok, so other people are seeing similar and it’s not easily fixable. I tried clearing cookies on the iPhone and maybe it made things better for 30 minutes, but that’s probably confirmation bias. I’m guessing that the difference between laptop and desktop (with nominally the same software) is that thi...
by arg
Thu Jul 08, 2021 7:30 pm
Forum: stardot FORUM
Topic: What controls forum login timeout?
Replies: 26
Views: 362

What controls forum login timeout?

I normally view the forum on a tab on my desktop machine (chrome browser), and there I can stay logged in for weeks at a time. Temporarily, I’m confined to bed and accessing via a flaky laptop or my IPhone. The iPhone logs me out very frequently- practically every time I close the phone, and sometim...
by arg
Wed Jul 07, 2021 6:39 pm
Forum: 8-bit acorn hardware
Topic: SD MDFS drive boxes
Replies: 32
Views: 796

Re: SD MDFS drive boxes

Some of my MDFS boxes are smooth glossy white: ...and according to that page were bought on two separate occasions. Was that finish some sort of deluxe model or special edition? I don’t think so. They were certainly that sand colour through most of the life of the MDFS (at least up to 1993 when I w...
by arg
Wed Jul 07, 2021 5:31 pm
Forum: 8-bit acorn hardware
Topic: SD MDFS drive boxes
Replies: 32
Views: 796

Re: SD MDFS drive boxes

philb wrote:
Wed Jul 07, 2021 4:33 pm
All that said I am slightly warming to the idea of the original blanking plate arrangement though I will have to give a bit more thought to the welding bit.
Adhesive rather than welding?

Yes, when you bring floppies into the equation it makes more sense.
by arg
Wed Jul 07, 2021 5:28 pm
Forum: 8-bit acorn hardware
Topic: SJ HDFS disk format
Replies: 23
Views: 730

Re: SJ HDFS disk format

How does your latest capture match up with the new one? The data there was suggesting that the byte offset to filesystem block zero was 0x20c00 My info suggests it should be 0x18800, though I think there was a re-layout at the point of switching to the multi-threasded version, as the upgrade instruc...
by arg
Wed Jul 07, 2021 4:03 pm
Forum: 8-bit acorn hardware
Topic: SJ HDFS disk format
Replies: 23
Views: 730

Re: SJ HDFS disk format

Somewhat weirdly there don't seem to be any sectors at all marked as bad in the Xebec flag bytes, and having read the description of how the Xebec handles bad blocks (two different methods) I don't think this would cause a change in the location of other data sectors anyway. Even if it did, bad blo...
by arg
Wed Jul 07, 2021 3:50 pm
Forum: 8-bit acorn hardware
Topic: SD MDFS drive boxes
Replies: 32
Views: 796

Re: SD MDFS drive boxes

The threaded bosses were cheap at the time- holes drilled before bending, then the bushes just locate in the holes and get a couple of touches with the welding tool to retain them. But as you say many acceptable equivalents: loose nuts, self-tappers, rivet nuts etc. But yes.the jigging for the weldi...
by arg
Wed Jul 07, 2021 3:15 pm
Forum: 8-bit acorn hardware
Topic: Troubleshoot loading cassette tapes
Replies: 54
Views: 1315

Re: Troubleshoot loading cassette tapes

I agree with the previous comments, but there’s something odd going on here and it really needs a look at a good PCB to confirm. Unfortunately I am not at home so I can’t look at my machine and I can’t find any images online of the underside. It seems most likely that the PTH and the pad on the unde...
by arg
Tue Jul 06, 2021 2:52 pm
Forum: for sale / freebies
Topic: BeebMaster BBC B Econet Kit
Replies: 203
Views: 13632

Re: BeebMaster BBC B Econet Kit

JLC specify 0.2mm clearance (or 0.4 if using V-score). Which is actually quite good. https://jlcpcb.com/capabilities/Capabilities I don’t know what they do if you exceed that- many places will silently cut back simple ground-fill that runs to the edge, but grumble if they spot any actual details in ...
by arg
Tue Jul 06, 2021 2:08 pm
Forum: 8-bit acorn hardware
Topic: FileStore restoration
Replies: 134
Views: 4520

Re: FileStore restoration

Slightly irritatingly the Adaptec SCSI card in the computer I was using there won't read any sectors from the Rodime. It seems to get upset because the disk is sending more data than it was expecting and I get "data overrun" errors. Maybe my best option is to hook it up to a BBC and read ...
by arg
Tue Jul 06, 2021 12:59 pm
Forum: for sale / freebies
Topic: BeebMaster BBC B Econet Kit
Replies: 203
Views: 13632

Re: BeebMaster BBC B Econet Kit

I've moved the tracks away from IC6p4&p5. I had them closer to allow the ground pour to run past that area, but I don't think that was too critical. What you have done now is way better- instead of the ground fill running decoratively down the edge of the board, it’s now working for its living ...
by arg
Tue Jul 06, 2021 9:25 am
Forum: for sale / freebies
Topic: BeebMaster BBC B Econet Kit
Replies: 203
Views: 13632

Re: BeebMaster BBC B Econet Kit

Right, I think I've sorted those routing issues now, on both IC5 and IC6. I've taken IC6p12/IC6p7 track around the left and bottom of IC6. I've also managed to find a way of routing R3 to IC2p4 without having to use an extra via. That all looks much better. It's a shame those two tracks along the b...
by arg
Tue Jul 06, 2021 8:13 am
Forum: 8-bit acorn hardware
Topic: The Beeb's cassette storage input circuit
Replies: 120
Views: 3108

Re: The Beeb's cassette storage input circuit

I'm not expecting it to be dependant on tone frequency. I think it will use the recovered RxD. When this is high, the ULA releases the RC network and C starts to charge through R. When the voltage on C passes the ULA logic input threshold, DCD is pulsed high. I think the delay will only depend on R...
by arg
Mon Jul 05, 2021 8:38 pm
Forum: for sale / freebies
Topic: BeebMaster BBC B Econet Kit
Replies: 203
Views: 13632

Re: BeebMaster BBC B Econet Kit

The main reason I looked at the 26LS31 is because it's another component that JLC can supply and fit. If I understand the various circuit diagrams correctly (oh, and thank you for pointing me towards the BBC circuit diagram for the 75159 arrangement) the Econet modules only ever use a single driver...

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