Technology correspondent, BBC News

Bletchley Park is best known for the work done on cracking the German codes and helping to bring World War II to a close far sooner than might have happened without those code breakers.

But many believe Bletchley should be celebrated not just for what it ended but also for what it started - namely the computer age.

The pioneering machines at Bletchley were created to help codebreakers cope with the enormous volume of enciphered material the Allies managed to intercept.

The machine that arguably had the greatest influence in those early days of computing was Colossus - a re-built version of which now resides in the National Museum of Computing which is also on the Bletchley site.

Men and machine

The Enigma machines were used by the field units of the German Army, Navy and Airforce. But the communications between Hitler and his generals were protected by different machines: The Lorenz SZ40 and SZ42.

The German High Command used the Lorenz machine because it was so much faster than the Enigma, making it much easier to send large amounts of text.

"For about 500 words Enigma was reasonable but for a whole report it was hopeless," said Jack Copeland, professor of philosophy at the University of Canterbury in New Zealand, director of the Turing Archive and a man with a passionate interest in the Bletchley Park computers.

Bletchley employed thousands of code breakers during wartime

The Allies first picked up the stream of enciphered traffic, dubbed Tunny, in 1940. The importance of the material it contained soon became apparent.

Like Enigma, the Lorenz machines enciphered text by mixing it with characters generated by a series of pinwheels.

"We broke wheel patterns for a whole year before Colossus came in," said Captain Jerry Roberts, one of the codebreakers who deciphered Tunny traffic at Bletchley.

"Because of the rapid expansion in the use of Tunny, our efforts were no longer enough and we had to have the machines in to do a better job."

The man who made Colossus was Post Office engineer Tommy Flowers, who had instantly impressed Alan Turing when asked by the maverick mathematician to design a machine to help him in his war work.

But, said Capt Roberts, Flowers could not have built his machine without the astonishing work of Cambridge mathematician Bill Tutte.

"I remember seeing him staring into the middle distance and twiddling his pencil and I wondered if he was earning his corn," said Capt Roberts.

But it soon became apparent that he was.

"He figured out how the Lorenz machine worked without ever having seen one and he worked out the algorithm that broke the traffic on a day-to-day basis," said Capt Roberts.

"If there had not been Bill Tutte, there would not have been any need for Tommy Flowers," he said. "The computer would have happened later. Much later."

Valve trouble

Prof Copeland said Tommy Flowers faced scepticism from Bletchley Park staff and others that his idea for a high-speed computer employing thousands of valves would ever work.

Colossus kept valves lit to ensure they kept on working

"Flowers was very much swimming against the current as valves were only being used in small units," he said. "But the idea of using large numbers of valves reliably was Tommy Flowers' big thing. He'd experimented and knew how to control the parameters."

And work it did.

The close co-operation between the human translators and the machines meant that the Allies got a close look at the intimate thoughts of the German High Command.

Information gleaned from Tunny was passed to the Russians and was instrumental in helping it defeat the Germans at Kursk - widely seen as one of the turning points of WWII.

The greater legacy is the influence of Colossus on the origins of the computer age.

"Tommy Flowers was the key figure for everything that happened subsequently in British computers," said Prof Copeland.

After the war Bletchley veterans Alan Turing and Max Newman separately did more work on computers using the basic designs and plans seen in Colossus.

Turing worked on the Automatic Computing Engine for the British government and Newman helped to bring to life the Manchester Small Scale Experimental Machine - widely acknowledged as the first stored program computer.

The work that went into Colossus also shaped the thinking of others such as Maurice Wilkes, Freddie Williams, Tom Kilburn and many others - essentially the whole cast of characters from whom early British computing arose.

And the rest, as they say, is history.

To some Steve Jobs is a national treasure and to others he is a visionary of the first order.

These are just some of the views being expressed in Silicon Valley about the Apple co-founder following the news he is taking a medical leave of absence from the company.

"Apple has become such an important part of the tech culture and they lead in so many ways with product visions, it's unclear that without that leadership which Steve Jobs can provide if anyone else can do that," said Mike Arrington, editor of the respected TechCrunch blog.

"He has single-handedly brought the US back into the mobile ball game with the iPhone. Until then it was all about Europe and Asia. He also broke the back of the music industry with iTunes.

"Those are two big legacies to leave behind, so I really believe he is a national treasure," Mr Arrington told BBC News.

Gene Munster, a senior analyst with Piper Jaffray seems to agree and told CNBC "replacing the magic of Steve Jobs is impossible."

Sympathy

Twitter, the micro blogging service, has been alight with users sharing and discussing the news.

The tweets range from those of sympathy and best wishes to Mr Jobs to questions about the future of Apple.

While one user tweeted "what will happen to Apple without Steve Jobs running day to day operations?" another added "he is awesome, but he's not the entire company people...."

That is the view of Van Baker who is a principal analyst with Gartner and covers Apple for the industry.

"The hit the stock price has taken was inevitable because he is the public persona of Apple and, largely wrongly, most people think as goes Steve so goes Apple.

"In truth it's not going to have an impact on Apple in running their business. They will do just fine. Tim Cook, who is taking over, is a very capable guy. He's not the personality Steve is, but he is very competent and Apple will do just fine," stated Mr Baker.

$64,000 question

While Mr Jobs' health has been a major topic of discussion following public appearances showing how gaunt and thin he had looked, many say they are not surprised he is taking such steps to get well.

A thin looking Mr Jobs at last year's WWDC reignited health concerns

Raines Cohen has been an Apple user since 1979 and helped found the Berkeley Macintosh Users Group, one of the largest of its kind in the country.

"I had been talking about organising a get well card for him so I really do wish him a rapid recovery.

"Apple has functioned without Steve in the past and I think it will do well. A few months away, I can't see it having any significant impact. Of course things can go longer."

This is not the first time Mr Jobs has stepped down as ceo of the company for health reasons. In 2004 following surgery for pancreatic cancer, he gave up the job for around six months.

Now with his second medical leave of absence , the question as to whether or not Mr Jobs will return takes on even more weight.

"That is the real question," suggested Mr Arrington.

"When a CEO steps down for health reasons, chances are they are not coming back.

"However he did come back after his bout with pancreatic cancer in 2004 so there is no reason to think he won't depending on how serous his health problems are."

Charles Wolf an analyst at Needham &Company who follows Apple said "It is reasonable to expect, given the history of Steve's illness, that the market is probably going to assume that he is not going to return to Apple."

Succession

As speculation starts to bubble about Mr Jobs' return or otherwise, the blogosphere is looking to Apple to map out its future more clearly.

The iPod is the world's most popular digital music player

At ZDNET, editor Larry Dignan said the "news is likely to start succession planning talk at Apple"

"It only seems prudent that Apple create and disclose a succession plan of some sort," he added.

Owen Thomas of the Gawker blog, said: "Apple needs to prove it can thrive without Jobs. And Jobs, for the sake of his family and friends if not Apple's investors must show he can thrive without Apple."

The Wall Street Journal noted that Mr Jobs has in the past talked publicly about the prospect of death and how it spurs him on.

In a commencement speech he gave at Stanford University in 2005, he told the crowd: "Remembering that I'll be dead soon is the most important tool I've ever encountered to help me make the big choices in life."

Slowing demand for computers has hit chipmakers

Slowing spending on computers saw Intel profits fall by 90% from $2.3bn to $234m (£159.6m) in the last three months of 2008.

Sales at the world's fourth largest chip maker slumped 23% to $8.2bn in line with the warning the firm gave earlier this month.

And it forecast sales of just $7bn billion in the first quarter of 2009.

IT departments are being cautions while domestic users think twice before buying new computers, analysts say.

The growing popularity of smaller netbook computers, which use lower profit margin processor chips, is also having an impact on the firm's takings.

Plans impeded

Intel shares rose 2.1% in after-hours trading with investors relieved the results were no worse than feared.

The severity of the drop was driven in part by a $1bn writedown in the value of Intel's investment in Clearwire Corp.

Clearwire works on a new type of wireless broadband that Intel is building into its chips - but there are fears that the credit crunch will impede its business plans.

PlanOn PrintStik PS910 review

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Verdict

Mobile professionals who need to print simple documents on the move may find the compact 700g PrintStik a useful travel companion. It's by no means perfect, but for some users the benefits will outweigh the drawbacks... Read Full Review.

Pros

• Stylish design
• Robust build quality
• Easy to use
• Bluetooth and USB connectivity
• Battery powered

Cons

• Text could be sharper
• Expensive to run
• Printed thermal paper curls up
• Only supports Windows PCs and BlackBerry devices at present

Key Specs

Size (W x H x D):	27.2 x 2.54 x 3.81 cm
Weight:	0.7 kg
Maximum resolution (b&w):	200 x 240 dpi
Maximum print speed (b&w):	3 ppm
USB:	yes
Operating systems supported:	Windows 2000, ME, XP, Vista; RIM OS (BlackBerry)

Read full specs

Steve Jobs's medical leave puts the spotlight on the other members of Apple's executive ranks.

Industry observers are looking in particular at chief operating officer Tim Cook, financial chief Peter Oppenheimer and marketing chief Phil Schiller.

Tim Cook
A former Compaq executive, Cook [pictured, top right] has run a lot of Apple's operations for some time. He was also the man the Apple board turned to when Jobs went on leave for cancer treatment in 2004.

Much of Cook's career has been spent in manufacturing and procurement, although he took over responsibility for sales at Apple, before acquiring the chief operating officer role in 2005. In addition to his work at Compaq, Cook also spent 12 years at IBM, where he ran manufacturing and operations for a large part of IBM's PC business.

Peter Oppenheimer
A long-standing finance specialist at Apple, Oppenheimer [pictured, bottom right] started with the company in 1996, serving as controller for the Americas, rising to overall controller, and then taking over as chief financial officer on the retirement of Fred Anderson.

Before arriving at Apple, Oppenheimer was a divisional chief finance officer at Automatic Data Processing.

Phil Schiller
Schiller has long served as Jobs's right-hand man when it comes to pitching Apple products to the public. He has been a frequent participant in Jobs's keynote speeches and has also given some solo talks, most recently at this year's Macworld.

An avid sports fan, Schiller coached an Apple ice-hockey team that took on a side from Sun, among other rivals. In addition to his work at Apple, he served as a vice president of product marketing for Macromedia.

While Cook, Oppenheimer and Schiller will have the highest profiles during Jobs's absence, others will also play key roles. Design guru Jonathan Ive is known as Apple's strongest creative voice after Jobs, while former Target executive Ron Johnson is responsible for Apple's booming network of retail stores.

On the software front, chief software architect, Avie Tevanian, is no longer at the company, but several other software executives remain, including software engineering head Bertrand Serlet and applications chief Sina Tamaddon.

Since its launch in September 2008, development of Google's WebKit-based Chrome browser has continued at an impressive pace. Unusually for Google software, Chrome exited beta status in pretty short order (100 days after the launch), showing how serious the search giant is about its web platform. Now a pre-beta of Google 2.0 (build 2.0.156.1) is doing the rounds. There are a number of enhancements in build 156.1, but, as we shall see, JavaScript performance is no different from that of the current stable version (build 1.0.154.43).

To get the latest version of Google's open-source browser, and remain up to date with future developer builds, download Chrome (if you don't have it already), then go to the Chromium developer site and download and run the Google Chrome Channel Changer and subscribe to the Dev channel.

The Channel Changer lets you receive Chrome updates with different levels of stability, the default channel being Stable.

To revert to a more stable channel, say from Dev to Beta, you'll need to reinstall Chrome and run the Channel Changer again.

Key new features

WebKit 528.8 Chrome 2.0.156.1 is based on an updated version of the open-source WebKit browser engine, which, among other things, enables CSS features such as gradients, canvas drawing, reflections and masks.

Form Autocomplete If you've typed an entry into a field on a web page, Chrome will remember it and bring up matches as you type.

Like Internet Explorer and Firefox, Chrome 2.0.156.1 now has an automplete feature.

Full-page zoom Ctrl + and Ctrl - now zooms all elements of a web page and not just the text, keeping everything in proportion. You can revert to the default view by pressing Ctrl 0.

Full page zoom in action: default view (Ctrl 0) is at the top.

Spell-checking improvements Spell-checking can be enabled and disabled, and different spell-checking languages selected, by right-clicking in a text field.

Right-click in a text field to access new spell-checking options.

Autoscroll Clicking the middle mouse button (or depressing the scroll wheel) turns on Autoscroll, whereupon you can move the mouse in any direction to scroll around a web page. Middle-click again to turn off this feature.

Autoscroll, with an arrow indicating the direction of mouse (and web page) movement.

Docking dragged tabs When you drag a tab from the Chrome browser window, you now have some handy Windows 7-style docking options, implemented by dropping the dragged tab on a docking icon. The drag positions and results are as follows: top of monitor = maximise dropped tab; left or right side of monitor = make tab half-width and full-height aligned to the relevant side of the screen; bottom of monitor = make tab full-width and half-height, aligned to the bottom of the screen; left or right side of the browser window = fit tab and browser window side-by-side across the screen; bottom of browser window = fit tab and browser window on top of one another.

Dragging a Chrome tab and dropping it on the docking icon on the side of the browser window causes the tab and the window to appear side by side, filling the screen.

Profiles Many people use the same computer (usually a notebook) at work and at home, and it's handy to be able to open a browser window with the appropriate settings. To do this in Chrome 2.0, simply select 'New window in profile', name your new profile and add a shortcut to the desktop. You can then set up the appropriate bookmarks, cookies and so on.

Chrome 2.0 supports browser profiles for different environments, such as work and home.