He added that the museum would also help engage new generations in the next stage of technological evolution by encouraging them not to take computers for granted.
He said: "Take something like the internet, which for many people is really extraordinary, the internet was really only invented in 1989, and here we are in 2008 and it's almost as if it has never not been there - it surrounds us."
For Phillip Dunkelberger, president and chief executive officer of data protection specialist PGP Corporation, seminal work in cryptology had been done at Bletchley - famous as the site where the Enigma code was cracked during WWII.
He also said there were important lessons learnt about the power of public-private partnerships to solve seemingly intractable problems.
He told the BBC: "I think that the people who set out to do their work every day, I don't think they set out to change the world by building the mainframe computer. And really they did it for the greater good.
To be physically engaged with the artefacts really puts the whole thing in context.
"Ultimately we would like to see it considered the first home. If you come to San Jose, we have the San Jose tech museum. I think it very easily could be the English equivalent."
Andy Clark, a director and a trustee at the museum, said he was thrilled by the donation.
He told the BBC: "This is a kick-start, these guys are really helping us out by getting us the support of the technology community really for the first time."
He said of the £7m the museum hoped to raise, about £1m would go towards restoration and curation and the rest would be entrusted to a fund to allow the museum to run without charging an entrance fee.
He said the British Computer Society had donated £75,000 and about £50,000 had come through personal donations.
He also emphasised that the museum was of computing, not computers, and that education was at the heart of its agenda.
He told the BBC: "It's where things happen - it's important that people can do things. To be physically engaged with the artefacts really puts the whole thing in context.
"You see that with kids, they stand in front of the Colossus and I say to them, do you realise this is a computer? And they say, 'it's very big!', and it catches their imagination."
The contribution by PGP Corporation and computer giant IBM, follows a campaign by the museum launched by a competition challenging volunteers to crack one of the toughest codes of WWII.
In July about 100 academics signed a letter to The Times saying the code-cracking centre, and crucible of the UK computer industry, was being allowed to fall into decay.
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