OVER 2 YOU, 057 (20/11/01)

ANALOGUE COMPUTERS

I would like to know if anyone has any information of knows where I could obtain plans for building an ‘analogue’ computer. I understand these were developed in the 1950s, long before the digital computers we use today. If possible or practical I would like to build one for a school science project.

D. Jackson, via email

As an undergraduate I worked exclusively on analogue computers. There are not many of us left now! There were many publications but almost all very mathematical and obscure. The standard text for students with worked examples is "Systematic Analogue Computer Programming; Charlesworth and Fletcher" Pitman '67, which is excellent. I have a copy, which I could loan gratis. There are two second hand books on www.2ndhand.org.uk.

It would be most interesting to see a report on the project.  Mr Jackson should be aware that he would need a patch panel and lots of operational amplifiers, potentiometers, and an oscilloscope display (or PC virtual equivalent).

Dr. Colin R Edwards, Mangotsfield, Bristol

The bible on analogue computers was written in the 1960's by "Korn & Korn" a husband & wife team. I can't remember the publisher but it may have been Academic or Wiley. Their amplifier designs were all of the thermionic valve type. I do not know if there was ever a successful commercial analogue computing system built around solid-state amplifiers but an Internet search for ‘analogue’ or ‘analog’ should flag that up.  It'll give some interesting magazine references too. They were all the rage in the 40's - 60's but as digital machines became faster, more reliable and easier to program the analogue machine's weakness sent it into retirement.
Robert Young,

A magazine called Practical Electronics published a series of 10 articles in 1968 covering the building of an analogue computer. I have originals of all the magazines and would be happy to provide photocopies. The articles include explanations of the working of an analogue computer as well as some examples after the constructional articles. The downside is that the circuits are all discrete (i.e. transistors, not integrated circuits), but anyone with basic electronic knowledge could probably work out how to use IC Operational Amplifiers instead. 

John Farmer,

Chapters 4 and 5 of "Electronic Computers" by S. H. Hollingdale and G. C. Tootill, Pelican Books, 1965 to 1976, ISBN 0 14 02.0524 1, give substantial general information on analogue computers, with some details of electronic ones. I think the book is out of print, but it sold very well, and libraries may
have copies. 

Geoff Tootill,

I am not so sure about building this type of computer, but I have used them for solving ordinary, linear differential equations in the past (about 1953 to the late 1960's). This was initially for the purpose of determining equations for the autopilots of guided missiles; the autopilots themselves were analogue computers that solved these equations. My feeling is that operational amplifier (op-amp) microchips can be used for analogue computer purposes, where it must essentially have negative feedback from its output to its input. This will be via a resistor for summation or multiplication-by-a-constant, and via a capacitor for integration.  In normal use the op-amp must not be allowed to achieve its maximum output capability. In this mode of use it is unlike its use in a digital computing sense.

Peter Fortescue,

Details of an analogue computer, which may be available in kit form can be obtained from: Limrose Group Ltd, Microelectronics Division, Llay Industrial Estate, Wrexham LL12 0Tclwyd, telephone 01978 855555
Mike Wilson,

RECORD COLLECTION

I would like to catalogue my Record/LP/CD collection. Can anyone recommend a good (preferably inexpensive) piece of specific database software to do this?

Simon Carter, via email

I have found a software program that will take any musical format along with a lot of information and categorise it for you in a database. It is called Arturo's Musical Sombra and can be downloaded from www.musicalsombra.com. It is freeware and I would rate it as a very good record logger for music.

Barry Mintz,

Try Catraxx from FN Programvare in Norway. A 30-day evaluation copy is available at www.fnprg.com.

Glen Buddery

I maintain a CD catalogue written in QBasic, which runs in DOS. The CD title, composer/artist and details for each track can be entered to a file to subsequently display or print one or two lines per track in either the title or the composer/ artist sequence. If Simon Carter is interested and contacts me I would be happy to send him a copy of the program with instructions.

Len Charlton,

There is a ready-made template in "Microsoft Access" which does a perfectly good job.

Jim Banks,

No problem! Try StarOffice 5.2. For about £30 you get an excellent database. Also thrown in is a word processor, spreadsheet, presentation graphics, diary, e-mail, browser and integrated desktop environment. Functionally it’s every bit as good as Microsoft Office, a fraction of the cost, a fraction of the hard disk space, reads a wide range of file formats and runs under all flavours of Windows, Linux and Sun's own SparcStation. It’s available from retail outlets on a single CD. If you have the patience, downloadable free from Sun's website. What's more, unlike Microsoft's bloatware, the £30 version even comes with a comprehensive printed manual! And, sadly, I don't have shares in Sun.
Dr Andy Graham-Cumming,

I can strongly recommend a software program from Newcastle based Elk Software (but only if the collection is mainly classical).  I have been using it for three years now without any problems whatsoever.  More details from: http://ourworld.compuserve.com/homepages/lion_elk/

Donald L. Marrison, Worthing, West Sussex

A visit to www.base40.com may well save Simon Carter much time and effort. CD Trustee is a brilliant program that not only lists and categorises CDs but also actually downloads track listings, timings, etc from an enormous central database. All you have to do is insert the CD into your computer's disc drive to be read, then hitch up and Bob's your uncle!

Jamie Doggart,

SPANISH CONNECTION

I am moving to Spain where I will not have a fixed telephone line and will have to rely on my cell phone for emails and surfing.  Has anyone in the same situation got any tips and are satellite phones viable or any faster than the 9200 bps connection speed on a mobile?
Colin Bailey, via email

For information on using a satellite link Colin Bailey’s best bet is to e-mail for details to leomarsol@wanadoo.es. They have shops up and down the Costa Blanca and can supply everything needed to interface a computer to a satellite dish and phone, for e-mail and TV as well. The whole kit is about £400.  Or he could look at www.prosoft-online.com. They are based near Alicante and can possibly help too.
N. J. Rowland,

TRANSPARENT PICTURES

I am compiling a Family History and, with a selection of male photos at various ages back to 1830, want to experiment with the superimposition of these photos to see how characteristic the facial characteristics of the family may be. Can anyone suggest a commercial program, which allows scaling and superimposition to generate a combined general image?

A. R. Warren, via email

Rather than use a bitmap image editing program to assemble a collage, use CorelDraw. With layers allowing bitmap and vector images to be superimposed, guidelines for positioning, plus all the drawing and text features that this great program has, it would be far, far superior. Once assembled, the combined image is exported as, say, a PhotoShop PSD file. The bitmap image can then be edited in the companion Corel PhotoPaint program including final sizing and resolution before saving as a JPEG file. CorelDraw 8 or 9 are available at remarkably low prices from the likes of CD-ROM Cellar: www.cdromcellar.com.

Don Perham,

CLIP ART

I use clipart quite a bit for a wide variety of personal and business projects (not websites). I feel I have exhausted the resources available in my (very expensive) off-the-shelf packages, and have turned to the Internet in an attempt to find new supplies.  However, I have found most clipart websites woeful in terms of quality, variety and styles.  Can anyone point me to some website gems with tasteful, stylish/arty, high quality clip art available for download, free or otherwise?
Felicity Berkeley, via email

Hemera have recently produced "The Big Box of Art" with (for PC users) with 180,000 clip art designs, 25,000 colour and 10,000 B & W photos, 103,000 web graphics plus other items. It costs £39.30 and is delivered from www.softwareparadise.co.uk, who are prompt and efficient.

Bob Reyner,

CAN YOU HELP?

I sometimes hear in my head music that I have never heard, but I can't read and write music so my melodies go lost.  Is there any software that puts into written music, a tune I whistle or hum?

Franco Cavallini, via email                          

I have been looking very hard (but perhaps not hard enough) for serious religious clipart. I'm looking for the standard that would give, for example, two hands holding a chalice, or two hands offering up a Sacred Host, plus of course any pictures of the inside of churches. Yahoo, Jeeves etc. only show me email addresses, which turn out to be standard 'comic' characters.  I'm not looking for freebies.

Gordon Hackwell, via email

In Excel it should be possible to calculate distances and bearing between any two Ordnance Survey map references, preferably as part of a "Route Card". Does anyone know how?
Cliff Mallinson, Nailsea, North Somerset