The Wren was one of the last "laptop" CP/M computer. It can be described as a combined personal computer and Teletext terminal. It weights more than 12 Kg !
This Computer was assembled at the Thorn EMI factory in Treorchy South Wales. Only about 1000 were made before Wren went bust and many companys were left holding the parts for the other 9000 units that were part of the first production run.
It was very advanced for its day and the software package was very good quality and comprehensive for that era.
Although the Wren computer was manufactured at Thorn EMI in Feltham, they were a subcontractor to Wren Computers Ltd. Wren was a joint venture company between Transam Microsystems (www.transam.co.uk) and Prism (who distributed computers for Sinclair). Transam have recently been aquired by Eurodata Systems.
The Wren was sold with several good softs : Perfect Calc, Perfect Writer, Perfect Filer, Executive Desktop (agenda, phone directory, note-pad, etc.), the popular BBC Basic (the same as the Acorn BBC or the Electron) and a communication application. Indeed the Wren has a built-in modem and is Prestel (english videotex) compatible. But it can also be used to automaticaly dial phone numbers stored in a directory.
The whole system looks quite strong and robust. When transported, the whole monitor and drive assembly slides over the keyboard. The 7" built-in screen is monochrome but it is also possible to connect the WREN to an external RGB monitor. The two disk-drives (40 tracks) can stored 190k each. Weird fact : the drives LEDs light up when one of the floppies is selected but don't light off when this drive stop to work...
Quality control was a major issue which certainly delayed production and caused a few financial problems for Wren. It might just have been too far advanced a concept for the time....
Great to see so many posts for the Wren. I would love to see any schematics or service information for this great little computer.
Wednesday 20th May 2015
Hi I have a Thorn EMI WREN in good working order.Also has its ts Mannuals and software ...Nice old pc
Sunday 16th November 2014
Mr N B Bell (uk)
Interesting... I was the hardware support specialist at Wren computers... I found this during a "nostalgia hunt".
The computer was very advanced for its time, but, as people have pointed out, plagued by problems.
The primary issue was the case itself. The design was very poor and EXTREMELY vulnerable to shock damage. There were quite a few sharp angles in the case mouldings that created weaknesses.
I cannot remember how many units we repaired, sent back to the customer , and which were returned again with cases that had been damaged in transit.
I remember testing out new packaging (+ possibly a slightly modified case?) by $ping boxes off a desk. (Corner $s, side $s, flip $s and so on).
I cannot remember with certainty if the design of the case was modified to try and make it less prone to stress damage, but I am pretty sure that the design of the case was modified slightly.
Also during manufacturing, we were unlucky enough to have batches of logic chips where the propagation times were all at the maximum specified values.. Units build using these chips often suffered from "amnesia". There was a lot of discreet logic involved in the RAM refresh circuitry, with bad propagation times through a number of logic gates all adding up, the memory refresh was unreliable. This was a difficult problem to find, and quite costly for Wren. The computers designer (from Transam Microsystems) used a lot of time tracking this problem down.
I took one home a few times, and had to swap arms several times on my way to the tube station. They were pretty heavy to haul around.
Friday 30th May 2014
Full-stroke keyboard with 5 function keys and arrow keys, 67 keys
Zilog Z80 A
64 kb (up to 256 kb)
80 x 25 / 40 x 25
512 x 256
monochrome built-in display
SIZE / WEIGHT
235 x 420 x 470 mm / 12 kg
Centronics, RS232c, Winchester Hard Disk, Paddle (2), Modem socket, RGB video output