A bit of fun: Which version of BBC Micro is the best?

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BigEd
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Re: A bit of fun: Which version of BBC Micro is the best?

Post by BigEd » Fri Jan 25, 2019 9:34 am

My very first impression of the Master was its ugliness. But shadow RAM is worth a lot! (I already had sideways RAM on my Beeb.)
Beeb, Mode 0, DFS: less than 6k free RAM.
Master, Mode 128, DFS: over 29k free RAM.

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dv8
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Re: A bit of fun: Which version of BBC Micro is the best?

Post by dv8 » Fri Jan 25, 2019 12:59 pm

Shadow RAM is even more useful on the Master than it was on earlier machines. Having independent control over whether the CPU, screen and VDU driver sees shadow memory gives opportunities, particularly for games, that are simply not possible on other beeb models.

For serious uses though, many of the advantages of the Master can be obtained by adding a cheap RPi second processor to a model B: extra user workspace, fully exploded character set, additional CPU instructions etc.

On a Beeb+Copro in mode 0 there is 30K free, or 44K with HiBASIC. Using machine code with no language ROM gives 60K free.

For me, the main benefits of the Master are the shadow RAM that allows double-buffering, improved filing system handling, CMOS configuration settings and the internal co-processor connector. Other things like the built-in 1770 fdc, sideways RAM, GXR etc are nice to have but can easily be added to a model B.

I've never been a fan of the Master's cartridge ports and the only time I've ever used the numeric keypad is to provide a donor key switch to one that failed on the main keyboard. :-)

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Re: A bit of fun: Which version of BBC Micro is the best?

Post by lurkio » Fri Jan 25, 2019 1:16 pm

dv8 wrote:
Fri Jan 25, 2019 12:59 pm
I've never been a fan of the Master's cartridge ports
They're handy for plugging one of these into though:

Mast_Cart.jpg
Photo of IFEL Master ROM/RAM cartridge

It's a Picton/IFEL/ctorwy31 Master ROM/RAM cartridge:
The author of the manual wrote:This card is an easy to use upgrade for the BBC Master. It is effectively the familiar ‘ROM cartridge’ but with a modern static RAM to provide additional benefits. For example, most cartridges can only accept two ROMs and, with a large number available for the machine, this leads to a lot of swapping of cartridges. However, constantly inserting and removing cartridges imposes wear on both the connector in the machine and also on the cartridge edge connector itself. On the other hand the use of RAM on the cartridge means that you can load different ROM images from disk (or solid state media) as and when needed. The RAM appears as two banks of 16kB in sockets 0/1 or 2/3, depending on which slot the card occupies.

The RAM chip itself can be thought of as containing four pairs of 16kB. The machine can only ‘see’ one pair at any time, and two switches are used to decide which of the four pairs are visible to the computer. You don’t have to the turn the machine off when altering the switches although a Ctrl-Break is usually needed.

The optional battery backup is provided by a single, inexpensive CR2032 cell and means that the cartridge data is retained even when the computer is turned off. Contrast this with the machine’s internal sideways RAM (link selectable in banks 4, 5, 6 and 7) which is always lost in the absence of power. Furthermore, and unlike the internal sideways RAM, the RAM on the cartridge can easily be write protected at the flick of a switch. Partial write protection allows one of the banks to be write protected and the other to be written to as normal. There is also a read inhibit facility so that you can easily recover from a crashed machine caused by a corrupted or problematic ROM image. The CR2032 should maintain the data for at least three years before it needs replacing.

An additional bonus is the presence of space for a single 28-pin socket which can accept a 16kB EPROM. This can be an ordinary leaf contact socket or even a ZIF socket. A single switch disables one of the banks of RAM and allows the ROM socket to be active instead. A ZIF socket can be especially handy when copying several ROM images onto a suitable filing system for use later in sideways RAM.
The standard Master command *SRLOAD can be used to load data into the RAM banks.
:idea:

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danielj
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Re: A bit of fun: Which version of BBC Micro is the best?

Post by danielj » Fri Jan 25, 2019 1:42 pm

dv8 wrote:
Fri Jan 25, 2019 12:59 pm
I've never been a fan of the Master's cartridge ports and the only time I've ever used the numeric keypad is to provide a donor key switch to one that failed on the main keyboard. :-)
As Lurkio said, they're bloody useful for ROMs :)

The numeric keypad is very useful with the 80186 when you're running dosplus. :mrgreen:

d.

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1024MAK
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Re: A bit of fun: Which version of BBC Micro is the best?

Post by 1024MAK » Fri Jan 25, 2019 2:30 pm

Numeric keypads are great when you are entering data that is (or nearly is) all numbers. I just wish that they all had at least one redefineable key, so that I could select a separated character of my choice...

Oh and a tab key as well...

At least the Master has a comma key 8)

Mark
Last edited by 1024MAK on Fri Jan 25, 2019 2:33 pm, edited 2 times in total.

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Re: A bit of fun: Which version of BBC Micro is the best?

Post by VectorEyes » Fri Jan 25, 2019 4:21 pm

lurkio wrote:
Fri Jan 25, 2019 1:16 pm
dv8 wrote:
Fri Jan 25, 2019 12:59 pm
I've never been a fan of the Master's cartridge ports
They're handy for plugging one of these into though:


Mast_Cart.jpg


It's a Picton/IFEL/ctorwy31 Master ROM/RAM cartridge:
The author of the manual wrote:This card is an easy to use upgrade for the BBC Master. It is effectively the familiar ‘ROM cartridge’ but with a modern static RAM to provide additional benefits. For example, most cartridges can only accept two ROMs and, with a large number available for the machine, this leads to a lot of swapping of cartridges. However, constantly inserting and removing cartridges imposes wear on both the connector in the machine and also on the cartridge edge connector itself. On the other hand the use of RAM on the cartridge means that you can load different ROM images from disk (or solid state media) as and when needed. The RAM appears as two banks of 16kB in sockets 0/1 or 2/3, depending on which slot the card occupies.

The RAM chip itself can be thought of as containing four pairs of 16kB. The machine can only ‘see’ one pair at any time, and two switches are used to decide which of the four pairs are visible to the computer. You don’t have to the turn the machine off when altering the switches although a Ctrl-Break is usually needed.

The optional battery backup is provided by a single, inexpensive CR2032 cell and means that the cartridge data is retained even when the computer is turned off. Contrast this with the machine’s internal sideways RAM (link selectable in banks 4, 5, 6 and 7) which is always lost in the absence of power. Furthermore, and unlike the internal sideways RAM, the RAM on the cartridge can easily be write protected at the flick of a switch. Partial write protection allows one of the banks to be write protected and the other to be written to as normal. There is also a read inhibit facility so that you can easily recover from a crashed machine caused by a corrupted or problematic ROM image. The CR2032 should maintain the data for at least three years before it needs replacing.

An additional bonus is the presence of space for a single 28-pin socket which can accept a 16kB EPROM. This can be an ordinary leaf contact socket or even a ZIF socket. A single switch disables one of the banks of RAM and allows the ROM socket to be active instead. A ZIF socket can be especially handy when copying several ROM images onto a suitable filing system for use later in sideways RAM.
The standard Master command *SRLOAD can be used to load data into the RAM banks.
:idea:
I've been waiting for months and months for Steve / IFEL to make more of those!

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lurkio
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Re: A bit of fun: Which version of BBC Micro is the best?

Post by lurkio » Fri Jan 25, 2019 11:18 pm

VectorEyes wrote:
Fri Jan 25, 2019 4:21 pm
I've been waiting for months and months for Steve / IFEL to make more of those!
I have a feeling you might not have to wait too much longer. Just a hunch....

:wink:

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