Chesterfield tram

Another video from the National Tramway Museum, a Chesterfield Corporation tram at work.

A legacy of spying

As well as Golden Age detective novels another literature love of mine is the spy novel, especially those by John LeCarré and Len Deighton. A few weeks ago I read the latest by the former, A Legacy of Spies. The story acts as a prequel to The Spy Who Came in from the Cold as well as a way of wrapping up the George Smiley saga which of course was at it's height with the peerless Tinker Taylor Soldier Spy.

The story involves old skool spying: dead letter drops, surveillance, micro dots, double agents. Set in Berlin just before and after the raising of the wall. It was a bleak time for Europe, so many human tragedies amid the brutality of the Cold War. The superpowers jockeying for position, endlessly testing each other's will and resolve. The threat of nuclear obliteration a very real one. My early years were spent under that spectre like so many people. Maybe that is one of the reasons I like these spy stories so much, a kind of nostalgia!

The book isn't perfect but is a fitting way to tie up so many threads, if you read it I highly recommend (re)reading The Spy... first though!

The fallen Berlin wall, scan from original photo I took

History of the World in Apple Objects (11) : PowerMac 7200

The PowerMac 7200 was one of the second generation PowerPC powered Macintoshes. It was introduced in 1995 with a PowerPC 601 CPU. The 7200 was a decent machine with CD-ROM, capable of running MacOS 7.5.2 up to 9.1 (though sometimes a bit slow on later OS releases). It came in the dull beige case common to Apple in the 1990s before the iMac and everything went colourful (for a bit anyway).

My 7200 was a work station at my first employer Tw2, used for producing web sites. Later it became a dedicated printer workstation. I rescued it when Tw2 went bankrupt.

IBM 2701 Data Adaptor Unit

Mainframes in the 1960s and 1970s such as the IBM 360 were huge complicated systems which filled large rooms. Some even had smaller (in relative terms - still large compared to the average machine now) computers to help them with the amount of information that was needed to be sent into them from a number of sources. These computers were known as Front End Processors or Communication Controllers and they handled data communications allowing the mainframe to concentrate on the jobs at hand [1].

The IBM 270x family, of which the 2701 Data Adaptor Unit was a member of, was an early example of communication controller and worked with the IBM 360 and 370. The 2701 "greatly expands the input/output capabilities of the IBM System/360" [2] by helping to interface to and control information flow from peripherals like the IBM 7701 Magnetic Tape Transmission Unit. The IBM 2701 was introduced in 1964 and replaced by the IBM 3704 in 1972.

Public domain image from SDASM Archives

[1] Barry Wilkinson & David Horrocks, Computer Peripherals (Edward Arnold, 1987) p. 281
[2] IBM 2701 Data Adaptor Unit Principles of Operation (IBM, 1965) p. 5

Stamford

Stamford is a delightful historic old town at the Southern tip of Lincolnshire and near to Oakham. The town is full of old stone buildings and alleyways, numerous churches, a rather nice Art Deco cinema and even the remnants of a castle. You can see my photos here.