Posts tagged with bbc-micro

Revisiting my BBC Micro - display, speech & more

It’s been a while since I blogged about Revitalizing my BBC Micro. In that time I’ve performed a few upgrades you might find interesting…

Display requirements

As useful as the tiny Amstrad CRT was I wanted something bigger, brighter and sharper. LCD is terrible for retro systems with blurry scaling attempting to draw images designed to take advantage of CRTs. Emulator authors spend significant effort trying to mimic CRT effects for a true retro feel but the best option is just to use a CRT.

Most machines in the 80s and early 90s were designed for TV compatibility and so operated on a 15KHz horizontal refresh rate. The VGA CRT monitors people struggle to give away aren’t going to work as they start at 31.5KHz. British machines like mine also use the PAL (UK) video system rather than the NTSC (USA) system - ideally a display would handle both.

If you don’t need any VGA frequencies then a Sony PVM is the way to go. I also own an Amiga 1200 which is capable of some VGA modes so it would be nice to have one CRT for everything. Multi-sync monitors can do both but were rare back then and are even rarer now and the shipping cost on CRTs limits can be prohibitive.

Commodore 1942 CRT

Figuring out resistor levels and sync signalsLuckily for me a Commodore 1942 CRT “bi-sync” turned up on Craigslist just 15 minutes from my house for $50. It was designed for the later Amiga models so it does both 15KHz most of my machines can do and some VGA resolutions too. Perfect.

Connecting it to the BBC was a little trickier than I anticipated. That Amiga design means it expects the horizontal (HSYNC) and vertical sync (VSYNC) signals on two different pins to match the Amiga’s video port rather than the composite sync (CSYNC) all my RGB capable machines offer (Amiga excluded).

I briefly experimented with connecting the CSYNC to HSYNC, VSYNC and indeed both but failed failed to get a stable display. Digging in to the Motorola 6845 CRT controller chip that powers the Beeb reveals both VSYNC and HSYNC on pins 40 and 39 respectively. A quick snip of the RGB port’s unused 5v and sync pins let me repurpose them to HSYNC and VSYNC direct on the 6845. A stable but over-saturated picture was a welcome next step that didn’t involve me needing to create a SYNC splitting circuit (I did that later to connect with my Spectrum +3).

Running Citadel on the Commodore 1942The over-saturation is because the BBC Micro outputs either 0V or 5V - off or on - for each color. The Amiga monitor is analogue and accepts any amount of color between 0V and 0.7V. I read guides on calculating the voltage drop but it still looked saturated so I kept increasing resistor values until I found values that looked right.

The final result definitely made me smile. It looked better than the Microvitec CUB monitors our school had back in the day without losing the CRT appeal. Success!

Speech synthesis

Hearing Superior Software’s SPEECH package blurt out any phrase we cared to throw at it was a blown-away moment at school. I’ve always wondered what the official Acorn speech system was like especially as every time I open the case empty sockets IC98 and IC99 call out for the Texas Instruments TMS5220 speech processor and associated TMS6100 voice synthesis memory.

The TMS5220 chip was a successor to that in Speak & Spell, Bally/Midway pinball machines and some arcade games as is quite easy to come by. The TMS6100 was available in many variants and the BBC commissioned some of their own including one sampled by BBC news anchor Kenneth Kendall. This chip is rare now and the fact the TMS6100 is not a regular ROM means you can’t just burn a copy. Thankfully Simon Inns created an emulator which can run on an ATMega32U2 to provide a drop-in replacement!

I obtained a TMS5220 and pre-built TMS6100 emulator board from Mark Haysman at RetroClinic who I can thoroughly recommend! (My SMT soldering skills are not up to this)

After inserting the two chips and powering nothing looks different. This command sequence however provides a good test mechanism:

TMS5220 chip and TMS6100 emulator board

REPEAT : SOUND -1,GET,0,0 : UNTIL 0

Pressing any key on the keyboard will cause the machine to say aloud the letter although it has some odd ideas about what the symbols on the keyboard are.

I will be experimenting with this more as I dig through the capabilities in the manual as it isn’t as easy to use as Superior Software’s Speech! which lets you type things like:

*SPEECH
*SAY Hello there.
*SAY I've got a bad feeling about this.

ROM experiments

My school had a single copy of the Advanced User Guide so I felt privileged when the teacher would let me borrow it although on reflection I doubt anyone else wanted to. Page 395 cryptically teases:

Up to 16 paged ROMS are therefore catered for, 4 of which are on the main circuit board.

So the OS supports 16 ROMs but there are only physical sockets for 4 (IC52, IC88, IC100 and IC101). Typically BASIC and the disc filing system (DFS or ADFS) take two of them leaving just two usable ROM sockets for expansion.

The schematics reveal IC76 is the ROM Select Latch and is a 74LS163 with 4 output pins thus providing 16 possible combinations - one for each ROM you could use so both the OS and the circuitry can support what we need if we could physically get the ROMs wired in.

The Beeb supports either 8K (2764) or 16K (27128) ROMs and EPROMs. Later 64KB (27512) chips became available which are almost pin-compatible with the 27128 except:

A collection of ROMs and an EPROM

27512 Pin 27127
A15 1 Vpp
A14 27 /PGM
/OE 22 /OE, Vpp

The /PGM and Vpp lines are for writing - an EPROM programmer will care about these but our Beeb won’t.

The A14 and A15 lines are the address lines for accessing the higher memory. With them both low the chip just acts like a regular 16K (27128) chip. With A14 high it looks to the next available 16K, with A15 high the next 16K and with A14 and A15 high the final 16K.

So what we can do here is combine four 16K ROM images into a single 64K file and flash it to our 27512 which is just what I did with my Signstek TL866A Universal USB programmer.

Now by connecting A14 and A15 to the IC76 address line C and D outputs we have effectively given whatever socket we connect this two the ability to appear as four ROMs (this works only because a single ROM can be paged in at a time).

The final icing on the cake is that the Beeb sports a push-out section left of the keyboard (affectionately known as the “ash tray”) where a zero insertion force - ZIF socket - could be mounted to allow a ROM to be dropped in without needing to crack open the case (our school was definitely not wanting us to open the machines and yet only one machine had this upgrade installed).

Now I just need to figure out how to mount this ZIF socket in the ash tray hole - there aren’t really any mounts. I suspect I’m going to need to make a PCB of some sort and put legs on it.

Building your own

Parts list

  • 28-pin ZIF socket
  • 28-pin DIP socket 0.6” wide
  • length of 28-way ribbon cable
  • 2.54mm header pins (you just need two)
  • 2x female-to-female jumper wires

Creating the cable

  1. Wire all pins from ZIF to DIP except for 1 & 27
  2. Solder two header pins to 11 & 12 on IC76
  3. Jumper ZIF pin 1 to 11 on IC76
  4. Jumper ZIF pin 27 to 12 on IC76

Now insert a 27512 ROM flashed with four BBC ROMs of your choice, power up and type *HELP or *ROMS to see the images ready.

Also check out alternatives for wiring up 64K ROMs or 32K SRAM chips from J.G. Harston

Second processor via a Pi Zero

The Beeb has a bunch of expansion ports hidden underneath the machine - the most unusual one being the Tube expansion bus which allows for a 2nd processor by way of a FIFO buffers that facilitated message passing IPC for console, errors, data and system calls.

Acorn produced a number of expansions for Tube including:

  • 6502 second processor allowing well-behaved unmodified programs to run faster
  • Z80 for CP/M
  • 80286 for DOS or GEM

Raspberry Pi Zero with Level ShifterThese expansions are hard to come by as they don’t just feature the CPU but necessary additional isolation logic, memory and circuitry. David Banks developed PiTubeDirect to allow a Raspberry Pi to act as second processor plugged into the Tube port by way of a 5V to 3.3V level shifter - I got mine from Kjell Sundby

The Raspberry Pi 3 can emulate these old processors as crazy speeds - 274MHz for the 6502, 112MHz for the Z80, 63MHz for the 80286 and even a 59MHz ARM2 (Acorn were using the Beeb to work on ARM prototypes)

What piqued my interest was using the Raspberry Pi Zero though. It’s small enough to fit under the BBC Micro and remain plugged into the Tube port out of sight. Latency was a problem on the Zero given the lower ARM processor so they ported the CPU emulation core… to the GPU!

The 6502 emulation is reliable and enabled me to run the 6502 Second Processor Elite. I definitely need to try and get GEM running on it just for fun although it’s a little trickier to find suitable disk images for Z80 and 80286 co-processor stuff.

[)amien

Revitalizing a BBC Micro

BBC attached to Amstrad monitor and giant twin floppy drives Moving house means making possessions count so my collection of vintage computers has shrunk over the years and the bar keeps getting higher. Right now:

  1. It works – Test it, repair it or part with it. A wealth of online technical information makes this easier than ever.
  2. A small footprint – Eject unusable peripherals and accessories. Keep the essentials.
  3. Make it usable – Forget slow-loading tapes and corrupt disks, a fast loading is essential.
  4. Something special – It should either be collectible or one I have a connection with.

Recent casualties were my Apple ][e (no disks), Acorn ARM (wouldn’t boot) and Commodore VIC 20 (poor state). Next up is my Acorn BBC Micro B:

Physical inspection

My ‘Beeb’ is in good condition and works well although the case screws have long since disappeared (a common theme in my collection) and it needed a good clean. These older mechanical keyboards attract serious dust and dirt.

Schools were filled with BBCs in the 80s and I’ve written about the origins of this love affair before. I learned first BBC BASIC and then some 6502 assembly (mixing it with Basic) while at school. I later picked this machine up around 91 after seeing a local paper advertisement.

A giant twin 5.25″ drive housing system (shown above) contained my one still-functional floppy drive. I want to be able to read some physical disks but in keeping with the minimal footprint I transplanted the floppy drive into a 5.25″ externally powered CD-ROM enclosure. Big reduction.

The BBC Micro has a few video output options – UHF, composite over BNC and RGB over 6-pin DIN connector. By a staggering coincidence the pin out is identical to the Amstrad CPC so works directly my Amstrad monitor, no adapter cable required this time!

Replacement media, SD cards via GoSDC

BBC Micro with SD Card fitted

SD cards are my replacement storage of choice for vintage systems. I chose John Kortink’s GoSDC for the following reasons:

  1. Supports MMC, SD, SDHC up to 32GB
  2. Internally fits into a spare ROM socket
  3. Adds operating system commands for great integration
  4. Supports disc images, tape images and ROM images

Retro Isle comprehensively reviewed GoSDC in February (2015) and have a bunch of usage tips and tricks too.

Getting started with GoSDC

GoSDC installed inside a BBC Micro model BThe device plugs into a ROM slot but to make life easy you can give it access to a second one so it can patch the filing system. The docs are complex as they describe the many possibilities available. Here’s my setup that works well on a BBC Micro Model B (known as Option B in the docs):

  1. Remove Acorn DFS ROM
  2. Fit GoSDC in slot third from right
  3. Fit cable from GoSDC jumper (middle-left) to pin 6 up from bottom right
  4. You should be left with the Acorn OS ROMs in the ROM sockets to the left of GoSDC

Once fitted, slide in an SD card and power up your BBC and you should see the usual welcome screen. Then type *SDCINFO and see the results:


BBC Computer 32K

Acorn DFS

BASIC

>*SDCINFO

GoSDC (mbe) 1.05 (01 Sep 2014)

ROM slots : main 15, free 13

Flash ROM : S25FL007, 1024 KiB

Flash card : SDHC, 7580 MiB

Available areas
---------------
X :     416256 bytes
1 : 4294966784 bytes
2 : 3653238784 bytes

>

If you see ROM slots main and free with numbers your device is correctly controlling two slots and can patch the DFS for you. If not, check the adapter and cable.

If you see “GoSDC : No flash card inserted” check the card is securely in and power cycle the machine. If it still doesn’t recognize it try another card. Note: When switching card you will need to press CtrlBreak for the machine to recognize it.

The first time you use a card you’ll need to format it. The command and subsequent output should look like this:

>*SDCTOOL SDCFO
Formatting area ... done
Verifying format ... ok
Please hard-reset your machine now
>

If you have a card greater than 4GB then it will create 4GB areas which can be switched between with *SDCAREA number. I’d recommend switching to the additional areas, formatting and CtrlBreak after each before you put any software on it as this command will wipe it out again.

Finally you’ll need to tell GoSDC to provide a patched filing system like this:

*SDCCONFIG FSNR 1
*SDCCONFIG FSRM 13
*SDCRESET
  • 1 sets Acorn DFS on my machine although the docs says it should be 2
  • 13 should match the free ROM slot shown in *SDCINFO

If you mess up your ROM selection and are unable to type because of ‘No drive’ do not fear! Press caps-lock and break twice to get the prompt back and choose another.

Finding old software

One option is to image all your floppy discs to SD card but you are probably going to find that those discs are corrupted. Thirty year old floppy disks are not reliable.

Another option is to download old software online. This can be a grey area as the software is copyrighted but no longer sold and many authors are okay with allowing it (e.g. Ian Bell and David Braben of Elite fame). A great site that honors the wishes of authors can be found at the weirdly named Stairway to Hell.

The author of GoSDC supplies Windows scripts to download, unpack and write the files to disc which I took the liberty of porting to Bash so they could be used on Mac OS X and Linux.

Purely based on subjective childhood experiences…

  • Elite a 3D space trading game so good they recently Kickstarted Elite 4
  • Citadel one hundred screens of arcade adventure madness
  • Chuckie Egg quick platform dash with birds, ducks, eggs and platforms
  • Repton Boulderdash to the next level, try 1 or 3, Repton 2 is insanely hard
  • Granny’s Garden educational fun alas distribution is denied as they sell an iPad version

Using GoSDC

Once the card is loaded up with software the actual commands are simple:

*SDCLIST

Will list the contents although you’ll probably want to put a wildcard after it to limit it down. Remember CtrlShift pauses the screen on the BBC!

Then, to mount a disc you use *SDCDISC and provide the name to mount. You can also use wildcards here and it will pick up the first match. e.g.

*SDCDISC *Chuckie*

Once mounted hold down Shift and tap Break to boot the game (or educational title, right?)

A few other useful commands are:

*. List contents of a disc
*EXEC !BOOT What ShiftBreak actually does
CHAIN "filename" To LOAD and RUN a BASIC program from disc
*filename To execute machine code programs from disc

I put some BBC Micro tips and tricks together or you can can grab PDFs of pretty much every book created for the BBC Micro .

You can also see which discs are currently selected using *SDCDISC with no arguments. You’ll note you can mount a second disc and the command to do that is *SDCEXTRA with usage otherwise exactly like *SDCDISC.

GoSDC can do much more including imaging your real floppy discs and writing them back out so be sure to check out the comprehensive documentation which also includes how to upgrade the firmware (use another memory card as that process uses FAT no the GoSDC file system)

Out for Pi Day!

Pi Day (3/14/15 = 3.1415) was last weekend and my work put on a session for kids about how to program the Raspberry Pi using Scratch and a bread board (using CanaKits so we had a bread board, LEDs, switches, wires, resistors etc.).

The original Raspberry Pi was heavily inspired by the BBC Micro and even the name “Model B” took cues from the original. Few people also seem to realize that the manufacturer of the BBC Micro – Acorn – went on to create a processor for its sequel the Acorn RISC Machine or ARM for short. That’s right, the Pi is powered by an Acorn processor design (like most smartphones) so it made sense to bring it in.

Alas it was a hectic event with little time to show the machine. In fact just sitting there it popped a capacitor in a puff of smoke!

Power supply repair

Despite the noise and smoke the dying capacitor didn’t actually stop the machine working as it is part of the electromagnetic interference suppression not the power circuitry itself. Still, it should be repaired and I thought I may as well replace the other X2 film capacitor as they have been failing over the last 30 years.

BBC power supply with blown X2 capacitor BBC power supply with new X2 capacitors

I picked up a couple of RIFA PME 271 M capacitors – 100nf and 10nf – (with a matching pitch so they would fit correctly) from Mouser for less than $2 each plus shipping. Five minutes of de-soldering and soldering later and it was good as new!

[)amien

Typography in 8 bits: System fonts

My love of typography originated in the 80’s with the golden years of 8-bit home computing and their 8×8 pixel monospaced fonts on low-resolution displays.

It’s quite easy to find bitmap copies of these fonts and also scalable traced TTF versions but there’s very little discussion about the fonts themselves. Let’s remedy that by firing up some emulators and investigating the glyphs.

Commodore PET (1977)

Commodore PET

Commodore’s first business machine was the PET which came with a built-in monitor and a full character set unlike other machines at the time.

Unusual characteristics

  • Primarily sans-serif but serifs present on ‘BDJa’
  • Slightly stylized ‘£’

Rationale

The font is good choice for the original PET and its original monitor. It was unfortunately also used on the Vic-20 despite having half the screen resolution where it made a poor choice.

Influences

While not visibly influenced from anything else an almost direct rip of this font appears to have been used in the Apple Lisa debugger.

Technical

Unknown.

Apple ][ (1977)

Apple ][ system font

Apple’s first professionally built computer was the Apple ][ which from rev 7 onwards added lower-case letters.

Unusual characteristics

  • Uppercase letters can touch descenders on the line above as the full height is used
  • Only first 7 columns per glyph otherwise would have been 35×24 text
  • Vertical stems for ‘[]{}’ are 2 pixels wide (bold)
  • Very small slashes ‘/\’
  • Upper-case is consistent although ‘A’ is very angular, ‘G’ unpronounced
  • Lower-case less consistent – ‘gf’ has soft curves, ‘mw’ square, ‘nhr’ ignore curve of ‘u’
  • Numbers – unusual ‘3’ but ’96’ over-extend

Rationale

The font is well suited to the default high-contrast white-on-black (often green-on-black) given the machine was intended for use on their own monitors.

Influences

The upper-case, numbers and symbols were copied from the Signetics 64 × 8 × 5 character generator 2513 chip used in the Apple I and II in revision 0 to 6.

The later Texas Instruments TMS9918 Video Controller Chip used on Sega, Nintendo, Colecovision and TI/99 machines re-used this font with only a couple of pixels changed.

Technical

Changing the font requires replacing the 2 KB 2716 pin-out ROM with your own EPROM or alternate ROM.

Atari 400/800 (1979)

Atari 8-bit system font

Atari’s entry into the home computing market put out some very capable machines with all sorts of hardware tricks (the creative geniuses behind it would go on to form Amiga). The same font was used on all Atari 8-bit models from the original 400/800 to the XL and XE models in the late 80’s.

Unusual characteristics

  • 6 pixels uppercase causes some vertical imbalance especially on ‘9’
  • Braces are overly bold being 3 pixels wide.
  • Less than and greater than symbols are too tall.
  • ‘MWw’ make great use of width to nice effect
  • Bar on ‘G’ too low, ‘U’ overtly square, ‘X’ very blocky, ‘S’ does not extend enough

Rationale

The machine boots in a low-contrast blue-on-blue and is designed for use with TV’s which explains some of the odd characteristics above like the square U to distinguish it from the V. It is likely the 6-pixel choice is to allow the letters to be centered when using inverse letter mode.

Influences

Designed by Scott Scheiman (Source)

Technical

One byte per row, 8 sequential bytes making one glyph. You can reprogram this by poking address 756 with the page number of the new font (default of 226 for ROM location 0xE000).

POKE 756, 226

Acorn BBC Micro (1981)

BBC Micro mode 1 system font

The Beeb, as it was affectionately known, has its own font which could display in three different modes – one wider and one narrower but many users might not recognize it all as it booted into ‘Mode 7’ utilizing a Videotex chip (used in the UK for text-on-TV and travel agents as well as in France for Minitel) that had a different font of its own.

Unusual characteristics

  • Drops bold in tight spaces e.g ‘$&@’
  • Outlines the tail on the ‘Q’ to make it much clearer
  • Unique and beautiful ‘*’
  • Does not extend low bar on ‘e’ as much as expected and ‘f’ seems to wide
  • Vertically squished ‘?’
  • Style of single-quote ‘ is inconsistent with comma

Rationale

The machine generally shipped with good quality monitors and the combination of high-contrast colors and this bold font made it very readable indeed.

Influences

It’s quite likely it was influenced by the Atari 8-bit font but with larger capitals and ascenders and a much more consistent look.

Technical

The system font is stored at 0xC00-0xC2FF with each character being represented by 8 sequential bytes (left pixel is high bit).

You can replace the font used by system text routine OSWRCH (0xFFEE) using the VDU command 23 followed by the ASCII code and then 8 rows of data, e.g.

VDU 23,65,11,22,33,44,55,66,77,88

Sinclair ZX Spectrum (1982)

Sinclair ZX Spectrum system font

Sinclair’s successor to the ZX81 added color and lower-case letters – again preserving the uppercase and numbers from its predecessor but finally mapping them to ASCII. This font was re-used on Jupiter Ace and Timex machines but the ZX Spectrum was the most popular.

Unusual characteristics

  • 6 pixels uppercase leaves many unevenly balanced ‘BEFS’ and ‘X’ with ugly 2×2 center
  • Full stop is 2×2 pixels (bold) but colon, semi-colon and comma are not
  • Capital ‘MW’ are very slight with latter hard to distinguish from ‘V’
  • Uneven styling ‘c’ omits curves, ‘e’ is soft ‘g’ is not, ‘f’ and ‘k’ are thin
  • Only the copyright symbol uses to the top row of pixels

Rationale

While the machine has a default high-contrast scheme the video output was poor because of the quality of the RF modulator and home TVs it was connected to. It looks like the designer decided to increase spacing between letters after the ZX80 from one to two pixels which greatly limited what could be done with the letters themselves. This was likely done for the same reasons it was done on the Atari 8-bit – namely to allow the letters to be centered when using inverse text modes.

Influences

The font was mostly inherited from the ZX80. I was not involved with that, so I don’t know who did it. Probably it was a combination of John Grant, Jim Westwood and Rick Dickinson. It’s possible we added lower case for the ZX81 or Spectrum (I can’t remember without checking), and I do remember discussions about how “mostly moistly” would appear.

Steve Vickers, email, 2nd February 2001

Technical

The system font is stored at 0x3D00-0x3FFF with each character being represented by 8 sequential bytes (left pixel is high bit). You can replace the system text routine (RST 10) by poking the new fonts memory address into the system memory map at 23606/23607 minus 256 bytes (the first 32 characters are non-printable, 32×8 = 256)

LOAD "newfont" CODE 49152, 768: POKE 23606, 0: POKE 23607, 191

Commodore 64 (1982)

Commodore 64 system font

Commodore took to take their success with the PET and applied it to the home first with the VIC 20 and then later with the wildly successful Commodore 64.

Unusual characteristics

  • Inconsistent shapes/style across ‘147,&<>@Q’
  • 2×2 pixel of ‘.’ is not carried through to ‘;:!’
  • Ascenders not as tall as capital letters

Rationale

The bold font was essential for the low-quality TV’s Commodore were aiming at. The inconsistencies across the font may have been intentional to help make the letters look different (A vs 4, 1 vs I, 7 vs T) given the limitations of the displays or just poorly implemented (see below).

Influences

Lower-case is identical to the Atari 8-bit font and likely copied wholesale as they do not match the upper-case well. Symbols, numbers and upper-case are a bolded version of the PET font that looses the serifs and also could explain the odd reproductions of 1, 2, 7 & 4.

Technical

See comment from Paolo below for details!

Amstrad CPC (1984)

Amstrad CPC system font

Alan Sugar’s foray into the UK market came a little later than the other 8-bits in 1984 with the Amstrad CPC series.

Unusual characteristics

  • Full use of 7 pixels for upper and 1 pixel for lower means glyphs can touch
  • Serif choice is unusual and not consistently applied because of space constraints
  • ‘0’ is wider than would be expected (copied from CGA font)
  • Very distinctive curves on ‘CGOQ’
  • ‘X’ looks like a different style because of high mid-point

Rationale

Sugar wanted the machine to look more professional than other home computers at the time. The choice of a serif based font to look like PCs which also featured serifs (at a higher resolution) reflects that desire.

Influences

Very similar to the IBM CGA font with some adjustments (fixes) to the horizontal positioning of some symbols. Many characters completely identical and some bearing style similarities too (wider 0, X choosing one side to be longer than the other). Some other characters bear similarity to the BBC Micro (Q uses the same trick to keep it distinguished) and a number of symbols and lower-case letters being the same where serifs would not fit.

The Amstrad CPC manual shows the system font but is different in some areas. It is possible it is a transcription problem (z is shifted up one pixel, missing pixels on ’37PRz~’ and extra pixels on ‘#b’ ) although it could have been an earlier version from the designer as ‘rG?’ are subtly different.

Technical

Redefine using the Amstrad BASIC command SYMBOL that takes an ASCII code and then 8 comma-separated values one-per-row in much the same way as the BBC with the VDU 23 command. SYMBOL AFTER must be set first e.g.

SYMBOL AFTER 32
SYMBOL 65,11,22,33,44,55,66,77,88

MSX (1983)

MSX system font

The MSX differs from the other machines here in that it was a standard rather than a specific machine. It was very popular in Japan and did hit UK shores although I only knew a single person that had one apart from our school which had acquired several Yamaha models to control MIDI keyboards. Given the multiple manufacturers, it’s not surprising that some models had slightly tweaked fonts but the one shown here seems to be the most popular.

Unusual characteristics

  • Full use of 7 pixels for upper and 1 pixel for lower means glyphs can touch
  • Only 5 pixels wide for the letters
  • Pixels touching on the curves of ‘db’ etc. look quite ugly
  • Very angular curves on ‘5’

Rationale

An unusual choice that feels very quirky.

Influences

Most likely influenced by the Apple ][e.

Technical

Unknown.

[)amien

Origins of a love affair

BBC Micro Computer's OwlFrom an earliest memory of a cream colored box emblazoned with letters, mostly black – some red, came an owl proclaiming allegiance to the BBC.

This small box sat silently, patiently even, in our classroom for the best part of a year. On the few occasions our teacher was brave enough to flip the switch the machine would chirp into life with it’s two-tone beep and would state on capital white letters on a black background that it was BASIC. At this point the teacher would key-in the mythical incantation of CHAIN “” – handily jotted on a nearby note – and feed the beast a cassette tape.

Some time later the machine would announce it’s vague disappointment with the contents of the tape and be put back to sleep. One time, and one time only, I recall a screen full of bright colors masquerading as pirates looking for treasure.

I was 11.

Such a tantalizing taste of computing left me hungry for more. I knew precisely two people who owned computers. One possessed a cut-down version of the BBC Micro from my classroom called the Acorn Electron and guarded it like a sacred treasure, the other was a friend and more accommodating so much so that he agreed, with little optimism, we could type my program listing into his computer.

What combination of childish scrawl, lack of understanding of programming concepts or the cobbled-together dialect of BASIC was responsible for his Texas Instruments TI-99 rejecting my program I would never know. However neither that failure nor the subsequent arrival and rapid departure of a ‘programmable’ Philips G7000 Videopac from my home would quench my thirst.

A new school year started and for me that meant a new school and new subjects the most interesting of these was named Information Technology or IT for short. I don’t recall much of these early lessons other than some exposure to word processing, videotext and a simplified geometry-base programming language for drawing shapes called Logo.

This fixed schedule held little interest to me although the machines themselves did and the teacher opened the room of fifteen or so BBC Micro’s equipped with 5.25″ floppy drives to the ever-changing line of misfits queued outside to play games. But unlike my old school a few people here actually knew a little about these machines.

Chuckie Egg and Mr. E were favorites while masochists would fire up Castle Quest, Citadel and Repton 2 despite being impossible to complete and lacking a crucial save-game option. Fewer still braved the open-ended and Elite space trading/combat game which would let you resume your position each day. Right on commander!

Games consisted of a few files passed between easily damaged 5.25″ floppy disks that students had mysteriously acquired. Remembering which file to CHAIN, *EXEC or *LOAD was a task in itself made worse by the ever-changing scene of kids and games. Now I finally had a machine to myself for a brief period each day I set about solving the first real world problem I encountered here and wanted to create something that would automatically boot and let you select a game by pressing a letter or a number.

Scouring magazines, loaning one of the few BBC BASIC programming manuals from the teacher and occasionally LISTing other people’s I came up with something that worked. Before long it had double height text, colors and some basic animation. Included in the program were some basic instructions on how to edit the program to fit the games on your own disk and it spread like wildfire.

Shortly after my father, who made gadget trading one of his hobbies, brought home a Sinclair ZX Spectrum 16KB. It was less powerful than the BBC’s at school and had to be hooked up to a television and cassette record to be of any use and had small rubber keys that were hard to type on. I played and programmed on it for hours without interruption and it finally became mine when my mother made it clear to my father it couldn’t be traded out for the next gadget. Within a few months the machine had died after something metallic got in through the edge connector.

I was heartbroken but found a neighbor was selling his Spectrum 48K and persuaded my parents to buy it. The extra memory was useful but even better was the hard-key keyboard and the original Sinclair BASIC programming manual I’d been missing. That year my parents split, my father moved out and we moved to a new parish on our little island of Guernsey which meant new friends and a new school. A school that had IT sharing lessons with technical drawing.

My hopes weren’t high…

[)amien