B+64K - 12k sideways ram working

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robert24
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B+64K - 12k sideways ram working

Post by robert24 » Sun Feb 18, 2018 5:19 pm

Have a B+ 64K that I am preparing for sale and wanted to see how I should list/explain the 12K "sideways" ram. It doesn't seem accessible by the SRAM commands in the DFS so wrote a small asm proggie to load a ROM image to it. After a few failures, tried loading an 8K wordwise rom that shows as a language rom and then using the FX142,128 command to select it.

Lo and behold... wordwise pops up and is usable. Loaded an old wp file and it all works. Can't see it in *ROMS or *HELP but it works. Have another few 8K "language" roms to try (Alligat, BCalc, Exmon, Toolkit, Beebmon) but it seems to work as a sideways ram/rom. After exiting with break, it even comes back with the FX command with the old data still available.

So feel reasonably confident saying it can be used to load "some" sideways roms. Happy that I can include a disk with the loader and some rom images. Otherwise it seems fairly useless. Never really found a use for the "shadow ram".

Happy dance :-)

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flaxcottage
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Re: B+64K - 12k sideways ram working

Post by flaxcottage » Sun Feb 18, 2018 5:39 pm

If you were to use 2 or 3 32K SRAMs plugged into one of the ROM sockets you could get 4 or 6 SWRAM banks. That's what I did with my B+ 64K. :D

The shadow RAM is great when writing software that needs hires graphics and/or colour graphics. MODE129 gives one much more memory than MODE1. If the GXR ROM is used the raising of PAGE is less important with shadow RAM. The same applies to using ADFS.
- John

Why do I keep collecting Acorn gear? I'm going to need a considerably bigger man-cave. :?

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robert24
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Re: B+64K - 12k sideways ram working

Post by robert24 » Sun Feb 18, 2018 5:46 pm

Post by flaxcottage » Sun Feb 18, 2018 5:39 pm
If you were to use 2 or 3 32K SRAMs plugged into one of the ROM sockets you could get 4 or 6 SWRAM banks.
surely it's not that simple? what ram chips are you using ?

We've seen an article with 3 x jump leads from a 256 ram chip but are you suggesting the rom sockets can simply take a ram chip?

do tell...
--
Thanks for a great Beeb resource :-)

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flaxcottage
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Re: B+64K - 12k sideways ram working

Post by flaxcottage » Sun Feb 18, 2018 6:01 pm

All the information is here via a link or two.

http://www.stardot.org.uk/forums/viewto ... de#p110602
- John

Why do I keep collecting Acorn gear? I'm going to need a considerably bigger man-cave. :?

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robert24
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Re: B+64K - 12k sideways ram working

Post by robert24 » Sun Feb 18, 2018 8:25 pm

All the information is here via a link or two.

http://www.stardot.org.uk/forums/viewto ... de#p110602
Ok, thanks for the references...

We have ordered one 62256 ram chip from the eBay and will try this version

https://martin-jones.com/2015/01/18/sid ... o-model-b/

We don't have any fly lead clips so will try to copy the [very neat] direct soldering. Hopefully it will all go to plan and our buyer can both load 8K language roms and play Exile with the speech extras [we remember "live or die", never got past that b****ard robot"]. Failing that, guess it will be up for "For parts or not working". Will post if anyone is interested.

As always, thanks for the assistance, praise be to you old BBC fogeys like us :-)

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Re: B+64K - 12k sideways ram working

Post by Coeus » Sun Feb 18, 2018 9:25 pm

Who do you think your potential buyers are?

I am thinking, for example, that I know what a B+64K is so I know it doesn't come with the normal kind of sideways RAM so that would not be a surprise. I also read that the B+ was generally less common than either the model B or the master which may help increase the price relative to either of those. I would not be certain that adding extras would necessarily increase the price. It all rather depends whether someone is keen to acquire a piece of history of whether they want it to be instantly as useful as possible.

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robert24
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Re: B+64K - 12k sideways ram working

Post by robert24 » Sun Feb 18, 2018 10:01 pm

Coeus wrote:Who do you think your potential buyers are?

I am thinking, for example, that I know what a B+64K is so I know it doesn't come with the normal kind of sideways RAM so that would not be a surprise. I also read that the B+ was generally less common than either the model B or the master which may help increase the price relative to either of those. I would not be certain that adding extras would necessarily increase the price. It all rather depends whether someone is keen to acquire a piece of history of whether they want it to be instantly as useful as possible.
Currently watching the BAFTAs so can appreciate the self-aggrandisement that sometimes accompanies some of the poorer examples of the Acorn/BBC computer series. To me, the B+64K is a bastard child of the Acorn/BBC stable. We recently sold another quoting the acorn marketing bumpf and felt that we were misrepresenting its usefulness. Ashamed ? Yes. Not really better than a standard BBC. Hence we tried to find where its qualities laid only to find that that would be really hard.

Would we buy a BBC B+ 64K now ? No. But with some investigation and a little effort it can be better than what was sold to an innocent public.

So with some effort... we CAN use the "sideways rom", otherwise discarded as simply a marketing statement.

I collected many BBC computers of all types and now am trying to divest ourselves of most of them without regard to monetary gain. The B+64K has proved the most problematic as I cannot honestly say that it is a "good" computer. By finding a way to use the RAM we at least don't feel that we are being dishonest about its abilities.

So... to answer your question: for BBC hard collectors, I will probably ruin the machine by making it actually more useful for BBC hobbiests. Why can't we load some roms into sideways ram and try out some of what those awesome programmers intended. If you would prefer an unadulterated B+64K, please let me know and I can offer that for sale here. either way, I intend to remove it from my real estate as I still have several B+128 and basic BBC B computers and I am finding it hard to decide of what to let go.

Thanks for making me think about our actions.

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Re: B+64K - 12k sideways ram working

Post by Coeus » Sun Feb 18, 2018 11:10 pm

robert24 wrote:...Not really better than a standard BBC...
It does have shadow screen RAM. That was an upgrade available to a standard BBC B back in the day - see viewtopic.php?f=3&t=14505 - but is the only such upgrade I can think of that doesn't have a modern re-make so that has to be worth something. There are options for sideways RAM. As well a DIY inserting chips and wiring lifted pins to other parts of the board there are various RAM/FLASH boards for sale.

On the "bastard child" description it seems to be that Acorn were playing catch-up at this point. The BBC B has been a tremendous successful but Acorn's favoured upgrade option of a second processor had sold less well and other companies were making add-ons that were rather cheaper. Shadow screen RAM and sideways RAM were two such upgrades. I also think Acorn were hampered in what they decided to sell as hardware by having a software house in the form of Acornsoft in that they wanted to avoid selling machines that would increase software piracy. The independent sellers of sideways RAM claimed various other uses for it such as RAM disks and enormous printer buffers but I suspect most people got it as a way to run ROM images which they would load from disc, not necessarily because they were too mean to pay for the original, but also because there were only four ROM slots. So it is interestingly that Acorn had a change of heart with the B+128K, though the extra RAM board shoe horned in suggests it was a bit of a last-minute thing.

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Re: B+64K - 12k sideways ram working

Post by SteveBagley » Mon Feb 19, 2018 12:13 am

Coeus wrote:So it is interestingly that Acorn had a change of heart with the B+128K, though the extra RAM board shoe horned in suggests it was a bit of a last-minute thing.
I wonder if the September 1985 Spectrum 128 announcement might have had something to do with the BBC B+ 128's creation?

Personally, the B+64K is my favourite Beeb since it was what I spent most of my childhood playing with… :)

Steve

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tricky
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Re: B+64K - 12k sideways ram working

Post by tricky » Mon Feb 19, 2018 9:40 am

I've always thought of the B+ as the "best" beeb, but since I found out about the masters "proper" Shadow ram (video), it's less clear.

For me, the B/B+ still wins as the master has the ADC at the "wrong" memory address and is missing the speech chip socket. The ADC address is easy to work around, but did it really need to move?

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Re: B+64K - 12k sideways ram working

Post by flaxcottage » Mon Feb 19, 2018 9:40 pm

BITD I preferred a B+ 128K to both the original Beeb and to the Master. The B+ has a much smaller footprint than the Master and has the shadow RAM and SWRAM found in the Master.

However, today I much prefer the Master. It is my machine of choice as it is much more versatile when it comes to attaching peripherals and it has the real-time clock built in. It can also be easily configured using the CMOS RAM and has cartridge slots for quickly changing ROMs. The addition of a Datacentre with CF HDDs and a Matchbox Co-pro make it simply amazing. :D

My B+ still gets used from time to time to satisfy my nostalgia. It has a turbo-MMC card fitted and dual 3.5" FDDs. I also fit an external Datacentre and a BeebOPL board to enjoy some retro melodies. :lol: I think I shall swap the speech chips from my network Beeb to my B+ too. I've programmed some 32K PROMs to use the B+ facility to use these so that I have more ROM slots available. With the 96K SWR I installed I can have the full complement of ROM images from 0 - 15. 8)
- John

Why do I keep collecting Acorn gear? I'm going to need a considerably bigger man-cave. :?

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tricky
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Re: B+64K - 12k sideways ram working

Post by tricky » Mon Feb 19, 2018 10:20 pm

Internal co-pro is nice, but matchbox or pi are practically internal.
Cartridge slots and a simple second user port, maybe the master does win :cry: would have been even better if it had sold a few million.

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Re: B+64K - 12k sideways ram working

Post by RobC » Mon Feb 19, 2018 10:34 pm

I used to use my B+ as my main machine but the Master has been my machine of preference for a good number of years now.

My two main issues with the Master are the lack of the speech interface and that there's only room inside for one 16KB ROM before you start to lose SWRAM. I know you can use cartridges but they are easily removed/lost.

If the B+ had the Master's shadow RAM implementation, I think I might have stuck with it for longer.

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Re: B+64K - 12k sideways ram working

Post by Coeus » Tue Feb 20, 2018 12:23 am

RobC wrote:My two main issues with the Master are the lack of the speech interface and that there's only room inside for one 16KB ROM before you start to lose SWRAM. I know you can use cartridges but they are easily removed/lost.
i don't have a master but if I were to get one I think the "upgrade" I would want to make is to program my own replacement for the mega ROM replacing view and viewsheet with things I would find more useful. That would three ROMs of my choice before having to resort to cartridges or sideways RAM. That would also mean being able to fix things like the Y2K handling. That obviously needs a daughter board as I don't believe programmable memories, either EPROM or FLASH are available in the pin-out of the existing masked ROM. I don't know if the existing "switchable OS" solutions support that or whether they just take two different versions of the masked ROM. I am sure I have seen a board recently that can be reprogrammed from within the master itself so maybe that is the answer.

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Re: B+64K - 12k sideways ram working

Post by danielj » Tue Feb 20, 2018 6:51 am

MultiOS can be reprogrammed happily (it's just an eeprom) - I've ditched viewsheet for anfs, put vanilla adfs back on it and it's already y2k patched... Myelin has developed a in-machine reprogrammable mega rom, I have yet to build/test that but it's moving up my list!

As soon as you have a HDD solution connected the sideways RAM makes a lot of sense as you can choose extra roms without having to take the lid off. Add to that a rom cartridge with a couple of ZIF sockets and you're away!

d.

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Re: B+64K - 12k sideways ram working

Post by crj » Thu Feb 22, 2018 3:06 am

flaxcottage wrote:However, today I much prefer the Master[...]
There are plenty of other reasons to prefer the Master:
  • Page at &E00
  • Exploded character set
  • Most of the Graphics Extension ROM built in
  • More sensible arrangement of the cursor keys
  • Break key both separated from f9 and with a safety catch
  • Tenkey (well, I used it!)
  • The ability to access files on filesystems other than the current one
I started out with a BBC model B, which I later upgraded with a disc interface, then a ROM board, then the Solidisk double-density disk interface. Everything did work, but it didn't really feel coherent any more. When the B got stolen and we got a Master, that felt like a far more polished offering, the ultimate expression of the 8-bit Acorn art.

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