You are currently browsing the archives for April, 2013.

About Prestel

April 22, 2013 // Posted in Main (Tags: , , , , , , , , , , , , , , , , , , , , , , , , ) |  1 Comment

In my first post I mentioned Prestel, and some readers have asked for more information on what it was and what it did, so here goes:

 

Prestel Logo

Prestel Logo

The innovations on which it was based were credited to Samuel Fedida at the then Post Office Research Station in Martlesham, Suffolk. In 1978, a team of programmers was recruited from within the Post Office Data Processing Executive. Under the management of David Wood they developed the software for the public access Prestel system. In 1983, as privatisation of British Telecom loomed the staff of the software development team were moved into the Prestel Division of BT.

Prestel was the GPO, later British Telecom’s, answer to teletext.  With two-way communications between user and servers, many more pages could be offered, and user interaction could be achieved through response frames to the Information Providers, user to user emails, and public chat lines.  It was launched in 1979.

The public Prestel database consisted of a set of individual frames, which were arranged in 24 lines of 40 characters each, similar to the display used by the Ceefax and ORACLE teletext services provided by the BBC and ITV television companies. Of these, the top line was reserved for the name of the Information Provider, the price and the page number, and the bottom line was reserved for system messages. Thus there remained 22 lines (of 40 characters each) in which the Information Provider (IP) could present information to the end-user. Each frame was stored in a block of 1 kilobyte (1024 bytes), out of which at least 104 bytes were reserved for routing and system information. This left 920 bytes for the frame contents, 716 bytes in the case of response frames. The IP logo on line 1 occupied at least 43 bytes, depending on the number of control characters, so the space available for the IP’s data is 877 characters at most. Lines could either occupy the full forty character positions, or be terminated early with a CR/LF sequence. Each control character took up two bytes, despite displaying as a single space, so the more complex a page, the less actual information could be presented. It was almost impossible, therefore, to display a right hand border to a page.

Available characters consisted of upper and lower case alphanumeric characters as well as punctuation and simple arithmetic symbols, using a variant of ISO 646 and CCITT standard. This layout was later formalised in the 1981 CEPT videotex standard as the CEPT3 profile. In addition, mosaic graphics were available in which individual character positions were divided into six squares which could be used in any combination, giving the possibility of 64 different graphics characters. Alphanumeric characters or mosaics could be entered in white or any one of six foreground colours (red, blue, green, yellow, cyan, magenta) and set against a background of the same colours as well as black. Special control symbols were employed so that characters or mosaics could be made to flash, appear double height, be separated by a border or be “concealed” (which were made visible by means of a special “reveal” button on the Prestel keypad).

By embedding cursor-control characters within the page data, it was also possible to encode simple animations by re-writing parts of the screen already displayed. These were termed “dynamic frames” and could not be created online using conventional editing terminals, but required specialist software and uploading via the “bulk update” facility. No timing options were available beyond that imposed by the available transmission speed, usually 1,200 baud download (receiving) and 75 baud upload (sending keypad entries).

The service was never as popular as it was envisaged.  Although it was taken up positively by the Travel and Financial services industries, the in-home market was never the success it could have been.  Televisions with built-in adapters were exorbitantly expensive, and hard to find, and dedicated terminals were only really affordable to businesses.

Despite this, Prestel was instrumental in developing many of the technologies we now consider commonplace on the Internet and World Wide Web today.  The Bank of Scotland had their HOBS “Home and Office Banking” service whereby you could manage your bank accounts online.  Club 403 offered online grocery shopping.  British Rail offered access to timetables.  Kays had mail order shopping from their catalogues.  There were several forums and chatlines where ordinary users could post messages and chat among themselves, and later, Micronet allowed anybody to publish their own pages, for a fairly modest fee.

Prestel was also instrumental in providing the first taste of electronic mail that many people would experience. Being able to send simple messages for free to friends and family would seem to be a novelty, but it would soon turn out to be one of the most used features of the service.  Many friendships were started and flourished through the interactions made possible via Prestel Mailbox, and Prestel was certainly responsible for more than one marriage, and perhaps the failure of several others.

Telex Link Info Sheet

Telex Link Info Sheet

To get more business users, Prestel launched Telex Link, which allowed any prestel subscriber to receive and send telex messages.  In the days before Fax machines, the telex was the official business-to-business communications medium:  Telex messages could be held to be legally binding just like a written letter.

In fact, it was only with the arrival of Micronet 800 in the mid 1980s, started as an online computer magazine by East Midlands Allied Press, and whom for a period gave away free modems for home computers with their subscriptions, that domestic usage began to rise.

This was helped by access only being a local telephone call throughout most of the country – a facility otherwise unheard of in the times before “0845” and it’s like.  Even so, Prestel subscriptions peaked at less than 100,000 subscribers – far below the “millions” of subscribers aimed for when launched.

During the daytime, when business usage was high, there was a per-minute charge to use Prestel, but in the evenings and weekends, traditionally the quiet times, it was free apart from the telephone call.

Unfortunately, with Micronet being so popular, suddenly the quiet times became fairly busy!

Prestel actually took over Micronet in 1989, and merged it with their other online offerings, forming the BT Dialcom Group.

In 1991, Prestel decided to introduce a charge during the previously free times, effectively doubling the cost of accessing the service, and within months managed to kill off the home usage almost completely, confirmed by the closure of Micronet that October.

After a decision to concentrate on core network services and not value-added services, the whole lot was sold off to a private consortium, and from there it ended up with Financial Express, where, after a brief appearance as ‘New Prestel’ it was closed down completely.

This is just a brief overview of Prestel probably one of the innovations that led to the Internet and communications systems we have today. The equipment that was used to create the Prestel service has all disappeared now it seems, not even is there any trace in any museum, unless you know better!

 

 

Some background

April 13, 2013 // Posted in Main (Tags: , , , , , , , , , , , ) |  1 Comment

 

For the first main post I thought I would give you some background on how I got into creating Software, Web Sites and Web Applications so here goes…

I was born at a very young age, and whilst I was at Grammar School got a Saturday and Holidays job at Currys, the Electrical People.

A Currys Shop

A Currys Shop

Morris-1000-Van-Currys

Morris-1000-Van-Currys

It was here that I got my first taste of technology, although it was very different to what we have today. The closest thing we had to a personal computer was Prestel from the Post Office. This involved a TV and a telephone line, and the data retrieved from the telephone was displayed on the TV, but it was only text, no images similar to Teletext.

Prestel Dr Alex Reid

Prestel Dr Alex Reid

Viewdata (Prestel) Ad

Viewdata (Prestel) Ad

When I left school I joined Currys full-time as a Trainee Manager, and it wasn’t long before I got my first store in a small market town called Diss, which is also where I went to Grammar School. The nearest we got to a computer at that time, was the Company Mainframe. All stock came with a stock docket, that was a machine readable piece of paper. When you sold the product you marked a line in a little box with an HB pencil and sent it off to Head Office. This along with millions of others, was then fed into a hopper and read by the mainframe and your stock was adjusted. A few days later you received a dot-matrix printed report detailing what had been processed.

I was promoted to Thetford, and this is where I got my first taste of a ‘personal’ computer. The Sinclair Z80 and Commodore VIC20 both arrived on the scene at around the same time. Both had memory of 2Kb. The Z80 was available only in kit form, and you had to build it yourself.

Sinclair ZX80

Sinclair ZX80

Sinclair ZX81

Sinclair ZX81

Commodore16/Vic20
Commodore16/Vic20

Later Sinclair launched the ZX81, which was available in kit or ready built form. You could add a 16Kb memory pack onto the rear connector to increase the ‘power’ of the macine, but if you moved the computer the connection to the ram pack inevitably came apart and everything you had done was lost. Saving programs and data on both the VIC20 and Sinclairs was done by saving the data to a standard cassette tape recorder, which was neither fast nor reliable. However, this is where I got my first programming experience. The Sinclair’s ‘Basic’ was not typed in as characters, but as key programming words, so if you wanted to use the PRINT command, you couldn’t type in P,R,I,N,T, whilst in programming mode, you pressed P, and the command PRINT appeared on the screen. You also had to have a TV to view the output from these computers.

The Apple IIe, the BBC and Acorn computers also appeared and they used 5¼” floppy diskettes. These too had limited memory and still no graphics.

BBC Computer

BBC Computer

Apple IIe

Apple IIe

Acorn Electron

Acorn Electron

I did some ‘real’ programming on an Apple IIe that my District Manager had been given, and wrote my first program that used data and stored it as separate data files from the users entries.

Later Amstrad started to devlop computers, with the Amstrad 64 and 6128, and later the 1512, 1640, PCW, PCW512 and then the PC2086, and PC2286.

Amstrad 64

Amstrad 64

Amstrad 6128

Amstrad 6128

Amstrad 1512/1640

Amstrad 1512/1640

Amstrad 2086

Amstrad 2086

The 64, 6128 and PCW range used CPM instead of Basic and DOS, It was similar to program as basic and I soon started writing applications for CPM. I wrote some applicatons for use by Area Managers at the Divisional Office and they were vey successful.

I was promoted to Divisional Office and soon started using the Amstrad 1512 with it’s dual floppy 5¼” disks and started learning Microsoft Basic. Graphical displays could now be achieved. But it wasn’t until I got into the Amstrad 2086, with it’s 3″ floppy diskettes (with hard plastic cover) and it’s 20Mb hard drive, that I got my first taste of Windows. (3.1). Although you could have several things open in ‘Windows’ at the same time, only one could actually run at a time.

Then things started to develop in leaps and bounds, first bulletin boards accessed via modems (300bps, and 1200bps/75bps) and then the Internet at speeds of up to 14.4Kbps, later 28.8Kbps and even 56kbps. This is when I created my first web site, everything was manually coded then, there wasn’t any fancy Web Authoring Software then and even images were limited as was what you could do with them. There wasn’t even javascript then either.

Over the next few years I changed jobs in the Currys/Dixons/PCWorld group and became more involved with writing applications in Paradox, Access and the like and also devloping web applications in ASP.

In 2006 I was made redundant, and later the same year took early retirement. This gave me plenty of time to spend on my hobby (computers) and to develop more software, web sites and web applications.

So there you have it, I have seen the advancment of the technology, from it’s infancy to the current day and like to think that I have developed and kept up with it too, at least a little anyway. And you know, all of the principles I learnt all those years ago, are still so relevant today, some may have been forgotten or not even learnt by some of the newer programmers now on the scene, but I will never stop remembering or using them where they are appropriate.

 

 

 

Welcome!

April 13, 2013 // Posted in Main (Tags: , , ) |  No Comments

Welcome to the phpmysite blog.

Over the coming months I will post articles related to php and some that have nothing to do with php.

I look forward to sharing with you.

It’s all about Why Not!

regards

 

Steve

%d bloggers like this: