Tuesday, 8 December 2015

Why I love Tandem Computers

Unless you are a teccie nerd, don't read on. Apologies for the 99.9% of my readers who this article will be completely incomprehensible to, but I simply had to make my feelings public for the 0.1% who will get it completely. Last week I went to the BITUG autumn conference for the first time in a number of years. For those of you who don't know what BITUG is. It isn't a bunch of swingers indulging in some odd practices, it is the Britain and Ireland Tandem User Group. And what is a Tandem? Well Tandem Computers were the worlds leading manufacteres of fault tolerant computer systems between 1974 when the company was set up until 1997 when it was acquired by Compaq (the company is now part of HP).

A typical Tandem Nonstop machine
I first came across Tandem Computers in October 1983, when  I got a job at SPL International, then one the UK's leading software companies. My official title, having completed an 8 week TOPS course in computer operations was Tandem Operations Controller. TOPS courses were set up by the Thatcher Government to address the then skills shortage in the IT sector (these days they take a different approach and they outsource everything). My job was to "look after the in house development machine". This meant doing backups, arrange maintenance visits, support the in house users and perform operating system upgrades. The system was a Nonstop II system. A 16 bit machine with four 477mb hard drives. These drives were 11 platter removable hard drives. The operating system revision was A06. The Nonstop II was the second generation of Nonstop computer. It had replaced the 8 bit Nonstop machine (rechristened Nonstop I). I had the pleasure of doing some work for SPL on a Nonstop I machine, as I was the in house operating systems expert. The last Nonstop I machine in the UK was operated by Dixons and controlled an automated warehouse system in Stevenege. SPL had supplied the system. This was my type of computer system. The Tandem controlled the largest train set in the world! Deliveries were scanned in and the Tandem would ensure that a whole series of rails and lifts stored them in the right place. At the other end of the factory was the goods out, where orders were automatically sent for despatch. It was a joy to behold.

The wonders of DynaBus
Tandem Computers were unique at the time in being "fault tolerant to a single point of failure". This means that if any one part of the hardware fails, there is another part that automatically takes over. Tandem developed there own special programming language called TAL, which is a block structured language, vaguely similar to C. Unlike most of the languages we see today, it is developed for high performance and data is directly addressed. If you only have 32k to deal with, you have to be pretty efficient. Due to their extremely high reliability and availability, Tandem Computers were bought by companies that required 24 x 7 availability. Customers of SPL included banks for ATM and payments systems, Air Traffic control and the airlines. Anything where you don't want your computer to fall over and be down for days. As you had to buy twice as much of everything as other comparable systems such as IBM and ICL mainframes, it was twice as expensive, but you had happy customers.

But it wasn't just the technology that made Tandem different. The ethos of the company was different. It was a Silicon valley startup, in the days when such things were novel. The company had a beer bust every Friday afternoon. This meant that the fridge full of beer was opened and the staff could get plastered on the company. It was a chance for staff to unwind. Customers were invited along as well. For people like me who worked on the technology, we had the satisfaction of knowing that we were working on the very best systems in the world. As Tandem was a far younger company than IBM or ICL, the people who worked on the technology were a generation younger than the IBM and ICL experts.

 I was especially lucky to work for SPL, who installed systems across the world. Every week teams were being despatched to places such as Switzerland, Saudi Arabia, New York and Brussels. Many of us had cheap weekends away, visiting workmates who were staying in such places. The best place to work in SPL was deemed to be BeNeLux (Belgium, Netherlands and Luxembourg).  You got great expenses and a fun environment. It didn't last, nothing does. SPL were bought by Systems Designers in late 1984 and the whole culture changed. SPL were a 'Tandem Shop' where as at SD, Tandem was a sideshow. We were told that they would be setting up an "IBM division" in our office. I was told that as I didn't have a degree I'd have to be regraded as admin staff. I told them to sod off. It was their policy to have 100% graduates as technicians. Although I stayed for another 18 months and oversaw the office move from Windmill St in W1 to Victoria, it was never really the same.

Despite the march of technology, Tandem computers are still in use. The vast majority of global ATM systems use Tandem technology as do POS systems. The UK rail reservation system runs on Tandems. At BITUG, we saw a demonstration the game Minecraft running on Nonstop server as HP now designates Tandems, but the main customers are large corporates dealing with the exponential growth of their core systems backbone networks. It is a testament to the technology that companies still use it for the systems that matter most to them.

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