Top 10 women of technology

2. Ada Lovelace
Iain Thomson: Now there's usually a disagreement or two when we hammer out the list, but the decision over the placement of the top two names was very hard fought.

In the end Ada Lovelace got the number two spot because the number one choice has had a more direct influence in our lives. While I can see Shaun's point, it was a bitter blow because she's been a heroine of mine for many years.

Lovelace was the world's first computer programmer, which is remarkable in itself, but even more so considering she was a woman in a time when most of her sex were considered only useful for producing children, preferably male ones.

Lovelace was a close associate of Charles Babbage, the inventor of the mechanical computer. She studied the device he was building and worked out how to get it to work in ways beyond simple number crunching, something Babbage himself had only an inkling of. Babbage called her his 'Enchantress of Numbers.'

On 24 March this year thousands of technical and non-technical people alike will celebrate Ada Lovelace Day, with events around the world to honour the first lady of computers and to rally support to get more women in IT. I still think she should have been number one on the list but some you win and some you lose.

Shaun Nichols: The last time Iain and I had a debate this heated was over the temperature at which beer should be served.

We've mentioned Lovelace before in our Top 10 lists, but let's rattle off her achievements one more time. As Iain noted, Lovelace not only managed to obtain a solid education as a woman, but was able to understand mathematics and engineering on a level that only a handful of people on the planet could manage at that time.

Lovelace not only thought of ways in which Babbage's analytical engine could be manipulated, but she went as far as to write an algorithm which could have been processed and solved by the engine. It wasn't just a theory; it was in fact the first appearance of the computer program.

Had Babbage's invention been appreciated and embraced as it should have, Lovelace would have become an historical icon. My apology to Lovelace for leaving her with the number two spot, but it is in no way due to a lack of genius.

1. Grace Hopper
Shaun Nichols: As Iain mentioned, there was a bit of a debate here, but ultimately the direct contributions of Grace Hopper beat the early visions of Ada Lovelace. While Lovelace showed a genius for mathematics and saw the huge potential of mechanised computing devices, Hopper's ideas dramatically helped to fashion computing as we know it today.

Whether man or woman, if you've ever written a line of computing code, chances are you owe a debt to Rear Admiral Grace Hopper. She helped to push the notion that computers should be able to recognise the notion of plain language. Among the systems that directly bear Hopper's fingerprints are the UNIVAC I commercial computer and the COBOL programming language.

This work helped to establish many of the early programming languages, and blazed the trail for the high-level software code that dictates personal computer and cloud-based application development today. Additionally, her reference to the removal of moths from early computer systems gives Hopper the honour of coining the term 'computer bug'.

Aside from a spot at the top of our list and countless awards and accolades, Harper's work in computing earned her something that would make any guy jealous: a US Navy Destroyer commissioned in her name, the USS Hopper.

Iain Thomson: Hopper was in at the start of modern computing and has done more to shape the technology world we have today than any other woman, and the vast majority of men.

During the Second World War she left her teaching post at Vassar and went to work on the original Mark One programmable computer and basically never stopped. Recognised as a mathematical genius, she worked on the Mark II before moving on to ENIAC and its successors.

She invented the compiler because, she said with characteristic modesty, she was lazy and wanted to get back to mathematics. Similarly Cobol was a successful attempt to bring programming into the mainstream, and its influence is still being felt today.

In later life she became an ambassador for computing. She would famously cut computer wires into 30cm lengths and hand them out to her students as a demonstration of how far light travels in one nanosecond to re-enforce that they should always aim to make their code tighter and faster.

She also worked tirelessly on the standards front, making sure that computers, and especially software, were tested rigorously and thoroughly.

However, there's a part of me that wishes she'd been born later. Hopper died in 1992 and never got to see the full flowering of the internet. We now need a new generation of Grace Hoppers to take us forward into the 21st century and beyond.