Saturday, 25 October 2014

A bit of geek nostalgia

 Anyone remember this? The Sinclair Z80, one of the first reasonably priced, ready built home computers to be found in the UK. You could either buy one ready built for £99.95, or save a few pounds by buying it as a kit and put it together yourself for just under £80. You needed to be fairly handy with a soldering iron, but that was no problem to me since soldering was part and parcel of my regular job. Of course once I knew it existed, I had to buy one as soon as I could and I was able to afford it because I had been saving up.
Not your usual kind of saving, but a long time back, just before decimalisation of the British currency, I had been keeping all the silver content coins in my change. Before decimalisation, coins had retained the same denominations for well over one hundred years and so there could be coins with all the different heads of past monarchs on them, including the odd Victorian coin. All silver coins were at one time pure silver and right up until 1946, there was some silver content in these coins and all this silver bullion was still circulating as loose change. So like a number of others around that time, I had collected a large set of pre-decimal coins, putting them into year sets and many of these were silver. Ten pounds value of the silver coins I had collected, I had worked out at current silver prices would earn me enough to buy a Z80 kit and have some money left over. I took the coins to a small dealer in London, I had seen advertise, who was offering a good rate of exchange.

 The place I went to turned out to be a really seedy looking shop in the Holloway Road. It was gloomy and unwashed looking inside and I was beginning to have some doubts that I was doing the right thing. The guy behind the counter was not very reassuring either, being just as scruffy as his dingy shop and as I approached the counter a large German shepherd lifted its head and growled menacingly. The guy never said a word the whole time and I offered him the packet of coins, thinking ‘I am going to be seriously ripped off here,’ whilst not quite having the nerve to turn around and walk straight out again. He counted the coins, weighed them and calmly peeled off one hundred pounds from a big roll of notes. I was astounded and very pleased because, despite my qualms, the guy had come across with a good deal and I had what I needed to buy my home computer and even some left over. 
The dog behind the counter in that shop looked a good deal less friendly than this one
The Z80 was not my first computer, a year or so before I had built a PipBug kit computer that I bought second hand from someone who had bought it and then decided they were not really up to the project.

The PipBug computer was about as minimal as you can get. It consisted of just a bare board, no keyboard, no power supply and no usable video output for a monitor. It had a whole 256 bytes of RAM. No that is not a misprint, not Gigabytes, Megabytes, or even kilobytes, there were just 256 memory cells and no means of storing programs you have written when you switched it off. To see what you were doing, it needed a terminal, something used with mainframe and expensive business computers at the time and one of those was way beyond my budget, so I built an Elector terminal kit, which provided all the electronics for a terminal without the screen or keyboard. You connected it to your TV for a display. I also had to build a keypad and a power supply.

It used machine code, so the keypad only needed sixteen keys or so plus a space and an enter key. This was easy to build and I was soon up and running, typing in a whole string of numbers in exactly the right sequence to get the device to display the word ‘HELLO’ on the screen. This after about twenty minutes of solid typing. My family were not impressed, but I was delighted and was jumping for joy. I was ecstatic, I had written my first machine code program and it worked. My enthusiasm did not last for more than a few weeks, because with no tape or disk storage, you always had to spend around twenty minutes or often much longer just to make something happen and what you got was not very spectacular or useful.

 When the Z80 came on the market, I was determined to upgrade. With the Z80, all the keys and display electronics were built in and all I had to do was connect it to a TV to get a display once I had put it together. The Z80 used BASIC and so now I had to learn that computer language. I had made a start at that too, because one of the things I had bought whilst still working in London was a Casio PB-100.

This was a programmable calculator which also ran on BASIC and I had used that to write short programs and so already had some knowledge of how to go about it, but it was still a steep learning curve.

To store programs and load programs on the ZX80, you had to use a cassette recorder, but since most households had one at that time, this was no real issue. A major problem of using a casette to store programs was the time it took to load a program. The accuracy of the reproduction of the cassette player was important. Any wear or dirt on the playback head would prevent a program loading and you would only know it had not loaded after you had waited for the tape to get to the end of the section containing the program you wanted. You could have more than one program on a tape, but had no way of indexing them unless you manually noted down the tape counter, assuming your cassette recorder had one and very few did, so even finding a program was problematical.
Pretty soon a generation of computer users had learned a new word, ’azimuth’. This related to the tape head adjustment, which had to be absolutely vertical or the higher frequencies of the recording were lost. On audio playback this merely muffled the sound a bit, but on a program recording the program would become unreadable. Since cheap cassette recorders were often not too well aligned, some would be a little off vertical. Borrowing a tape from someone else often resulted in failure. Adjusting the head to match the borrowed tape worked but then your old ones would not work, likewise if you had to buy a new cassette recorder your old tapes would not load until you readjusted the azimuth. So computer buffs became very good at adjusting and re-adjusting the playback head of cassette recorders.

The Z80 had some major idiosyncrasies besides this. It only had 1kb of memory, which was a bit limiting, even though it was four times my old PipBug. It could only output the display when the processor was not working on a program. This meant that the results of your program were only displayed at intervals and no animation was possible. The display was black and white and mostly characters with a few crude blocks for simple graphics.

 The following year Sinclair released a much improved computer known as the ZX81. This allowed proper displays that could be animated, but still only in black and white. Both the ZX80 and the ZX81 could be expanded to 16kB of memory if you bought the expansion pack. I eventually bought a ZX81 and an expansion pack and I started to write simple games programs. You could by now buy a lot of software for the ZX81, including a word processor and it is rumoured that Terry Pratchett wrote his first Diskworld novel, The Colour of Magic, on a ZX81.

The year after that, building on the success of the ZX80 and even greater success of the ZX81, Sinclair released the Spectrum. A colour computer that had 16kB of memory built in. This proved to be a real winner for Sinclair and sold millions. Long after its release in 1982, I upgraded from my ZX81 to a spectrum.

Now the boys were old enough to become interested in them and soon I was sitting watching them use my computer, unable to get near until after they had gone to bed.

The Spectrum was much more like a home computer should be. It was able to produce colour animated graphics and could be upgraded eventually to 128kilobytes of memory. You started to be able to buy a lot of additions for your Spectrum that plugged into the rear connector, which allowed printers and even a hard disk to be connected. The keyboard was not special, so you could also buy a kit that allowed a better keyboard to be added to the original works by replacing the top half of the case with a much more useful set of real keys.

A more sophisticated version replaced the spectrum case entirely and you fitted the inner workings inside a 102 key keyboard.

The larger version was almost the same as PC keyboard
Pretty soon I was tinkering with the inner workings of the spectrum and fitting a reset button, a break key and re-writing the ROM to add little touches such as replacing the copyright Sinclair notice with my name. I was able to add more memory without having to buy the Sinclair kit. There was a bug in the original Spectrum ROM which could be exploited if you knew how and many off the shelf programs used this. If you knew how you could, with my added break key, halt a program in the middle and then reverse engineer the code to make your own version. This was not possible on an unadulterated Spectrum and was a little close to infringing someone’s copyright, but we did not think of those things then.

By this time the number one son had his own Spectrum and was writing programs of his own. The number two son never got into computers quite to this level, having written his own program at age eight, he lost interest in that side of it and moved on to war games.

The BBC could have a number of peripherals, such as a floppy disk drive and its own monitor.
Eventually we both upgraded to the BBC computer and tinkered with that instead. The BBC was a lot more sophisticated in many ways, although it used a less powerful processor than the Sinclair computers, it had a neat trick where you could add all sorts of extra functionality using what they called Sideways RAM and Sideways ROM. These were extra panels that you could fit inside the computer where it expanded the capabilities of the system enormously.  It had a built in keyboard and was a lot bigger than the Sinclair computers plus a great deal more expensive but fairly soon you could buy a second hand BBC for a reasonable sum.  The BBC computer was sometimes used in industry and I was amazed once when doing a tour of the local sewage works, as you do, to find they were controlling much of the waste water processing via a bank of BBC computers. The BBC was the last of our pre PC computers and by 1990 we were building our own PCs from off the shelf components and were getting into DOS and Windows. Mind you things were very different then as my first hard disk was 32Mb in size; the maximum DOS could use. It was not until I installed Windows that I could increase the disk to 100Mb and it seemed to me at the time a huge amount of storage space. When you consider that you can now get drives of six Terabytes, which is 60 thousand billion more storage, things have moved on a bit.
One of the interesting side effects of the 80s boom in home computers was that it generated a lot of software savvy computer geeks and many years later when I was teaching computer programming, we started to find a skills gap in our younger candidates. These were people who had not grown up in a house which had an 80s style home computer, but had only ever seen a PC. They had never had to learn programming and so, when they came to us, we had to start teaching them the basics at a much lower level before we could get onto the main syllabus. Something that, thanks to 80s home computers, we had not needed for many years after Sinclair introduced his home computer range. This skills gap is now being covered by the introduction of small hobbyist computers like the Raspberry Pi in schools and so school leavers may soon have caught up with the 80s generation of children.

Saturday, 11 October 2014

Farewell to Summer

Summer is long gone and I am a bit late with my summer blog this year, but now the weather has started to become more autumnal, it is worth looking back at the long hot summer we had this year. Not everyone may agree with that and may wonder where we were that was hot and dry for any length of time, but we have been remarkably lucky with the weather this year and everything we did we managed to make it between bursts of less favourable weather apart from the first day we were on holiday.  For a short time we had a huge thunderstorm and some hailstones that were the biggest I have ever seen in Great Britain, but after that, the weather was really good.

A huge hailstone, starting to melt
This summer it was the turn for the American side of the family to come visit. In order to accommodate everyone, we hired a holiday home in the Cotswold Water Park not far from Cirencester. Although this is right on our doorstep, it provided us with enough accommodation for all of us and is a central point from where our family could explore the Cotswolds. Not that we are new to the Cotswolds, but both The Son (TS) and The Daughter’s (TD’s) families do not often get to see this part of the world, since fleeing the nest and making their own way in the world and both had married someone who did not come from this part of the world at all. The place we stayed at is on a large gated estate full of private houses that are either the holiday homes of the individual owners or places for short term hire for people like us who want to spend some time there. None of the houses were used as permanent homes since the estate is not classed as a residential site, but a leisure area.

The place we hired was a three story house with a large open plan ground floor overlooking one of the small lakes within the water park.

 However, due to the reeds and bushes that surround the lake, the view of the lake is only visible from the upper floors.

Pretty soon we were reminded that we were close to water because every time a window was opened, we soon found a number of Damsel flies, which somehow had easily found their way in, but now finding it impossible to get out again. The grandchildren spent some time helping them out, but with little overall success.
 Damsel flies are very much like small blue dragon flies, but their wings are not quite the same, which is one way of identifying them.

From the Cotswold Water Park we made several forays into the surrounding towns and villages and also a couple of trips into London, via the nearest railway station. It is easily thirty years since I last attempted to drive into London, long before congestion charges and other restrictions, because traffic approaching London make the journey difficult, besides the difficulty of parking once there, so rail or coach travel has been my preference for some time . Because there is so much to see in London, we could not fit in everything each person wanted to see into a single trip, so we split up into two groups. The first group for people, who wanted to include Madame Tussauds on their trip and the second for those who wanted to include the Imperial War Museum . These were arranged for different days, so whilst those not going had a quiet day in the Water Park, the other took the train into London. The Better Half (TBH) and I joined in the second day since TBH particularly wanted to visit the Imperial War Museum’s First World War Centenary exhibition in the morning and then go on to the British Museum, to see the more famous pieces there.

As an aside, a family rumour claims that the waxwork figure of Madame Tussauds, the founder of the waxworks, is wearing a bonnet made by my great great grandma who was a milliner and did work for the waxworks.

I do not know if this is true. Even if it was true once, the present day waxwork figure would be unlikely to still have same bonnet. My great grandmother was born a couple of years before Madame Tussauds’ death and her mother, my great great grandmother certainly was a milliner, who like Madame Tussauds came from France around the same time, so it is possible.

Kemble station, devoid of trains
Our trip to London was not straight forward. When we arrived at Kemble Station, and after I had bought an all-day ticket for the car park, we were told there was no train. There had been a signal failure and we could either wait an unspecified time for a bus to arrive that had been summoned by Great Western to take passengers on to nearby Swindon Station, or forgo our parking fee and drive ourselves to Swindon to catch a train there. Since the bus could be anything in the order of thirty minutes before it could get to Kemble, let alone on to Swindon, we decided it would be sensible to drive ourselves. Of course, the parking fee for Swindon is about four times that of Kemble, and we never did get our money back from Kemble Station, there was not enough time to deal with that if we were to get to London before the museums closed. Owing to the train not passing Kemble and other local stations before Swindon, the train we caught was virtually empty and we were able to occupy some reserved seats, since the people who booked them had been unable to catch the train and so could not claim their seats.
 On arrival at Paddington, we discovered that the London Cross-rail project work had closed a number of Tube stations, including the Bakerloo line entrance at Paddington. This required a long  walk along underground walkways to find the alternative entrance and we opted to leave the station and walk on to Edgware Road above ground, which is no great distance from Paddington and under the circumstances considerably less crowded than going via the underground tunnels. Once safely on the Bakerloo Line train, we soon arrived at Lambeth North and made our way to the museum. At the museum entrance, we were greeted by museum staff handing out timed tickets for the WWI gallery. The place was heaving and they were controlling how many people went in to that section of the museum at any one time. It did not seem to very effective because you could barely move when we finally got in. The changes to the main gallery, we all agreed, were not an improvement and the WWI display when we got into it was not quite as good as we had been led to expect. The whole exhibition seemed to be mostly based around the Western Front, with little about any other theatres of war from that ‘World’ war. Since TBH’s Grandfather died in Mesopotamia and is buried in a grave just outside Baghdad, we were disappointed to find very little on that aspect of the war other than a very small section on Gallipoli, with nothing very much about the rest of the Middle Eastern campaigns.

Parking can be difficult in London.  
Well you may have guessed, it is really one of the exhibits in the main gallery. Once we had struggled through the crowded museum and seen all we wanted to see, or just got fed up with fighting through the crowds there, we headed off to the British Museum via Tottenham Court Road station and into familiar territory for me. I once had an aunt who ran a dance school in Bloomsbury Street and the British Museum is just around the corner from there. As a child, on days when we visited my aunt there, the grownups would want to chat and whilst they were talking we were often sent off to the museum to keep us out of mischief. Kids were allowed out on their own in those days, even in London.
Tottenham Court Road was a later haunt of mine during the sixties and seventies, because that was the best place for hobbyists to obtain components for building electronic equipment. Many of the major suppliers like Henry’s Radio and so on had shops in Tottenham Court Road. The surviving shops have long since moved out of London due to the excessive cost of maintaining a business inside the M25.

In the British Museum, I found it rather different from my childhood memories. To be honest, from time to time although I lived in West London and I often worked in and around central London, I have never been back to that museum since I was a child. The addition of a large circular Millennium structure in the centre of the main entrance was a surprise, I had not been aware of that project. This took up a huge amount of space, limiting the exhibition to the galleries around the central square. For a building in central London, it must be costly in terms of unused square footage. Since all commercial buildings in London pay through the nose for every square inch of floor space, this seemed to me a bit of a waste.
So far I have failed to mention the weather we were experiencing that day. It seems that we had picked one of the hottest days of the year to visit London, which has its own climate anyway, one that is generally a few degrees warmer than the rest of the country. On looking at her smartphone, a by now rather hot, Daughter in Law (DIL) discovered to her relief that the British museum has one of the best air conditioned interiors of the London museums and public galleries, so we were a bit disappointed to find it was steaming hot inside and the only thing resembling air conditioning was a swivel fan stood by one of the archways between galleries. We looked at some of the larger exhibits whilst I wondered where all the smaller ones that I remembered had gone. I recall rows and rows of small items from Roman times plus exquisite carvings from the Egyptian section that always fascinated me as a child because they were so well made. To my mind they were so much better than they had any right to be, they should have been crude and badly made since they were ages old. Ancient people should have been primitive, all my children’s literature showed hairy savages in animal skin loin cloths waving clubs, so their perfection always astounded my childish mind. Although I found a very small display, I could not find the rows and rows that had fascinated me so as a child. I assume that the museum changes the exhibits around from time to time and they must have a store somewhere to keep all those things they do not have room to display, but as far as I could see, they had made the museum seem empty. Compared to the Pitt Rivers Museum in Oxford, where there are masses of interesting items crowded together on the displays, which gives you the chance to discover new treasures every time you visit, in many ways, although it exhibits some incredibly important objects, the BM was a lot less interesting than the Pitt Rivers Museum. This is not to say that we found the BM completely uninteresting, we were able to see the Elgin Marbles and the Rosetta Stone and many other things that I had never appreciated as a child, so it was worth a visit, despite the heat.

Part of the Elgin Marbles in the BM. Many more are in a museum in Holland.

An awe inspiring piece of work.  Carved so perfectly and polished to a smooth finish.  It must have taken forever.
The journey back to our Cotswold base was uneventful, having been able to catch the train in which we had reserved our seats, but although the tickets said Kemble and the train went right through, we had to get off at Swindon because our car was still there.

 During the rest of the two weeks we spent in the Water park, we toured around the local area and visited several places.  One of these was Bourton on the Water, with the shallow Windrush River passing through the centre and its reiterative model village.

This model cottage reminded me of the illustrations in the Little Grey Rabbit books my sister used to have. They always had a drawing of her house inside the front and back covers
Little Grey Rabbit's cottage as illustrated by Margaret Tempest, stories by Alison Uttley

A fossilised car found in the model village.  It may have been painted once, when the model village was new.
 Whilst we were there, we also visited the Dragonfly Maze, which entertained the children and most of the adults by containing a puzzle that you have to solve as you find your way around. Once you have made it to the centre of the maze, there is a small building containing a glass case with a toad in the centre. If you have solved the puzzle correctly, you have a set of instructions on how to get the toad to open its mouth and reveal the dragonfly. The grandchildren were given a paper answer sheet each and a pencil as we came in and they had to write the clues down as they found them, although some of them are a puzzle too, so you have to guess the right word from the clues. Once you have them all written down in the proper order, it made up a sentence which gives the sequence of actions needed to open the toad’s mouth. Unfortunately my camera battery ran out just as the kids had managed to reveal the dragonfly, so I was unable to take its picture.

The toad inside its glass case with its mouth closed
On leaving the maze you hand in your answer sheets and the kids got a small prize for getting all the clues right.

On another trip, we went to Oxford and wandered around the older parts of town. I first went to Oxford when I was a very small child and was fascinated by the bridges there, but for many years I did not know where these fabulous places were, until I met my first wife, who was born in Oxford.  Although she did not live there any more, I had to pass through Oxford to reach her home and we visited Oxford together from time to time. I then re-discovered the bridges from my childhood.  In those days, you could drive right through the middle of Oxford and out the other side on the A420, but during the 70s, the road was blocked to through traffic and now it is very nearly pointless trying to drive into the centre of town, so we used the park and ride service to get into town.

One of the bridges that so facinated me as a child
The dreaming spires
I can never go to Oxford without visiting Blackwells bookshop, it being one of the most impressive places and has such a wide range of books that you must surely find something of interest to you. The shop front is small but the interior is on many floors and stretched back a long way, particularly the basement floor.  I bought a couple of classics I had never read and a couple of popular science books.  One on the life and work of Richard Feynman and another on the search for the Higgs Boson.
Bibliotheca  Bodliana
Whilst on the subject of books, we also visited the Bodleian Library, something I had always meant to do, but have never gotten around to.
The interior was really spledndid and the glass in the windows, gave a ripple effect showing it was not modern glass.
The main library is still in use and the guide had to whisper, but being a little mutt and jeff, I was hard pressed to hear what he said and on mentioning this I was invited to stand closer to him, which did not help a great deal, so I did not follow the history too well, 

 Outside the Bodleian, there was an open air theatre set up ready for a performance of Shakespeare that evening.

I thought that the ranks of  chairs produced an interesting pattern with their legs dwindiling into the distance
Close to the Water Park is the ancient Roman town now known as Cirenceter, or Siren to the locals. When my two boys were young and conkers were an important part of their lives, we would go to Cirencester Park and collect conkers from the tree lined avenue which stretches off into the distance as a grand entrance to the main estate. In Cirencester we went with the family to the Corinium Museum where, as well as the normal exhibits of Roman, Celtic and medieval objects, they have produced a number of full sized tableaux representing everyday life in Roman and Celtic Britain. One of these is a Roman cavalryman on a full sized model of a horse. Near the beginning there are three Celtic figures, a man a woman and a boy. I am unsure what this is supposed to represent, because the boy is threatening the man with a spear and the woman is admonishing the child. Unfortunately my imagination immediately captioned this scene with; ‘It’s all right son, this is Uncle Badvoc, he is going to live with us now daddy has gone.’

Further in, there is a Roman family scene with a group of people sitting around in a typical Roman sitting room. They are all sitting looking towards one corner of the room with the exception of one person who is standing. They all look pretty glum and in my imagined caption for this scene she is saying; ‘By the Gods Claudius, someone has stolen the TV!’

Aside from my irreverent take on their displays, they have packed a lot of interesting material into a relatively small space and a number of interactive displays and puzzles for children. Amongst the medieval section are some small stone carvings of faces which once adorned a church and one is a portrait of the then pope and this particular face is amazingly realistic.

Cirencester has a large number of eateries for such a small town and we were able to eat there one or two days during our holiday. Living nearby, Cirencester is familiar to me and TBH and we occasionally shop there, so we knew where to find the best places, but did not take advantage of our local knowledge since we were travelling around and only went there a couple of times. One place we did eat at is an (allegedly) American Diner style burger bar who do some passably good burgers. Whilst we were there I commented to one of the staff that having the word 'Toilet' on the door to the loos, was out of character and they should be labelled Rest Room if they want to be more authentic. Recently TBH and I were amused to find that the sign had been changed and now reads Rest Room. One thing that is a bit of a hoot, to coin a phrase, is the sign over the bar, right next to a display of the different milk shakes available advertising Hooters. Hooters are, of course, a thoroughly respectable chain to go to for a meal if you like your waitress to be very feminine and to serve you in a very skimpy uniform. It goes one step further than the Bunny club and seemed a bit odd to be advertised alongside children’s milk shakes.

In common with a lot of British towns, Cirencester has a small antiques gallery, which has several rooms on two floors full of cabinets and alcoves containing everything collectable from bric a brac to ancient Roman and other even older antiquities. Several members of the family and myself love this kind of place and can spend hours looking through the stuff there and in my case, wishing I could afford some of the wonderful stuff you find, whilst at the same time wondering where on earth I would put it, if I did buy that large Victorian mercury barometer, or the beautifully carved gigantic chest and so on. During our fortnight’s holiday, my birthday was due and I was asked what I would like for a present and in the really old stuff display was a Luristan copper arrowhead about 3,000 years old, a little before my time, but small enough to fit into a crowded house and I liked it a lot, so the family clubbed together and bought it for me. I was delighted. These things are not rare and so are not hugely expensive, but it was nice of them to buy it for me and it now on the wall of my study.

Another outing was to Stratford upon Avon, the home of The Bard and we visited the grave of his nibs whilst there, something I had not done before.

Add caption
A few days into the holiday I had broken my best pair of glasses by sitting on them and they were just about held together by a loop of copper wire and some superglue. Stratford is where our optician is, and so whilst there TBH and I booked an appointment to have our eyes tested. The weather was still doing us proud and so TBH and I wandered around the town, whilst the family visited some of Shakespeare’s houses. We did not bother with most of them, being familiar with these from frequent visits. In Stratford, there is another of those antiques arcades and I spent a little while looking, but did not buy anything this time.

Pretty soon, it was coming to the end of the fortnight and we had to pack up everything and TBH had to take TS and his family to Heathrow and say goodbye for another year. TD and family were going to stay with us at our house for another two nights, so that firstly TSIL could visit his eldest son and his family down towards Portsmouth. They would then be returning to us so that we could all celebrate their wedding anniversary, a date that is hard for me to forget, since it was the same date as my mother’s birthday. After the meal, they stopped overnight and then they had to wend their way back to Cumbria and we were left alone once more.