DSL Systems 40 years on written by its founder Paul Girdham


It seems amazing that it was in 1979, 40 years ago, that I started Design Software Ltd. as it was then called. A few years later when ‘software’ was getting a bad name and the name ‘Design Software Limited’ was a bit of a mouthful, the Company was re-named DSL Systems Ltd. In the beginning we had nothing; I borrowed a table and chair from


a friend and ran the Company from my flat in the centre of Nottingham. We had a company called Aircall to answer the telephone if we didn’t answer it within five rings and they would take a message. Our first purchase was an IBM ‘Golfball’ typewriter so that we could produce professional quotations and documentation. I seem to remember that it cost about £600 which was a lot of money 40 years ago. The first computer we purchased was a DEC (Digital Equipment Corporation) LSI-11 with twin 8-inch floppy disks and 28k of memory. This ran a real- time operating system called RT-11. This computer cost in the order of £8,000 which was a substantial amount of money and equivalent to £32,000 now. Of course, PCs hadn’t been invented in 1979, the first IBM PC only arriving in 1981. We moved out of my flat in Newcastle Drive and into the top floor


of an old Victorian building nearby on The Ropewalk in Nottingham. Computers in those days were so big and heavy, we even had to employ a Structural Engineer to advise on how to reinforce the floor in one room. Later on, we were so full I remember having to sit on the window sill for a few days because there wasn’t enough room for a chair.


BOCM Silcock (later in 1992 called BOCM Pauls and more recently taken over by ForFarmers) and others. The first animal feed mill which we worked on was Eagle Mill for Pauls Agriculture in Ipswich (since demolished). The control of the weighers was notable as each weigher used a SOW-400 (Select-O-Weigh) unit about the size of two shoe boxes to control it. These SOW-400s were designed and built by Howe Richardson Scale in Nottingham and impressive because they did everything using an early Intel 4004 (4 bit) processor! Now, we normally have 64-bit processors even on laptops. Later on, we designed a complete computer control system


for Howe Richardson called SOW-900 which was designed for the manufacture of rubber – somewhat simpler than an animal feed mill but an awful, dirty environment with carbon black powder getting everywhere. In 1987 DSL moved out of the centre of Nottingham and into the


newly built Highfields Science Park close to the University. Computers were still big and we still had to extract hot air from our ‘computer room’ in summer. In the late 1980s we acted as consultants for the control systems


for a couple of feed mills (John Thompson and Sons, Belfast and BOCM Silcock, Selby). After these, in 1989, we asked BOCM if we could quote to provide the complete control system for two mills for them (Blandford Forum and Exeter) ourselves. This was the first time we were to design and supply the complete new control system ourselves and provide all the hardware. We will be eternally grateful to Andy Vincent who was then the Chief Engineer of BOCM Silcock and took the decision to fund us for four months while we designed and wrote our first system, called LBC25 (Large Batching Control for 25 scales). This was a centralised control system using a VAX mini-computer running the VMS operating system with PAMUX Input /Output cards and using very early PCs running DOS for the separate graphic displays. I still have, on the wall of my office, a printout of the very first batch from BOCM Blandford


Above: DSL’s computers on the strengthened floor In the 1970’s a factory control system normally consisted of a huge


hardwired mimic with lamps, buttons and switches and lots of wiring and relays to do the interlocking. However, this was changing with computers and PLCs (Programmable Logic Controllers) doing more and more of the logic. In the beginning, we only wrote the software for a variety of control companies – Howe Richardson Scale (later re- named Chronos Richardson), W & T Avery the weighing company in Smethwick (later re-named Avery Berkel), British Gas (East Midlands),


PAGE 46 SEPTEMBER/OCTOBER 2019 FEED COMPOUNDER


Above DSL’s very first LBC25 batch record (1990)


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68