Colossus & Other Early Computers 

So glad you gave Tommy Flowers the credit for building Colossus. A most interesting look at the history of computers in the UK.

Hard to believe that we carry computers in our pockets now that are over a million times more powerful than these old machines. Interesting video ! I really enjoyed this. :)

This channel feels like the 80's technology shows I watched back then. I absolutely love it.

7:46 "200MB of storage" Damn, who could possibly use that much storage? Nobody will ever need more than 50MB.

I bought at auction a box full of old valves, a few of these were MOD stamped and red. Just the types of valves colossus used, and I was able to donate them to the late Tony Sale to help his rebuild. I actually met him and a really nice guy.

I worked at DEC Digital Equipment Corp back in 1978 -1981 then from 1983-1985 I first started to work on hard drives similar to the one's on the ILC system but they were made by CDC Control Data Corp. they were 200-300 MB 20 heads (two for each platter one platters was a servo signal to keep all the data heads aligned.

Enjoyable video, thanks. Would love to see more historic computing episodes, covering the 70s, 80s and 90s!

It is quite amusing though, how a computer only 60-70 years ago could easily fill an entire room, whereas today we have tiny little boards the size of a couple fingers such as the Pi Zero which cost about $10 and still has insanely more processing power, while only consuming as little as 5 watts, it may not be the scifi world people dream of but it's still pretty amazing sometimes.

Many thanks for showing us around TNMOC, CB@EC! The nice thing about the very early computers is that they are constructed from a few hundred conceptually simple units including logic gates, shift registers, adders, a clock, some sort of memory, and so on, which implement maybe a dozen instructions, making it possible, with a little effort, to understand exactly how they work. Thus, although they are quite simple things, these primitive computers appear to be almost miraculous thinking machines, simply because they can perform repetitive operations, tirelessly, at rates significantly greater than a human being is able to do.

Holy shit, now I feel old! I used to work on the 2966 when I was a young engineer at ICL back in the eighties :) Now it's in a museum, hehe.

I wrote code for and managed ICL1903a, 2966 and Series 39 machines. We used them for stock control, payroll and some more esoteric stuff such as radio frequency prediction. At the time I could program in COBOL, S3 which ICL programmed much of VME in. There was a Fortran compiler and an Algol 60 compiler for both the 1900 and 2900 series systems. I also implemented some systems on an ICL DRS 20 system, which was one of the first networked 8 bit microprocessor systems ( unusually I think ICL bought the design in and badge engineered it, the mainframes and associated operating systems were done in house) . I guess this was in about 1985. They were still running payroll and personnel for about 200,000 people back in the 1990s. It's quite interesting to consider how little computational power and storage mainframes had but how much work they could get through. And how efficiently one had to code to get a program to fit in say 4 megabytes of memory. It's quite ironic really because now I program microcontrollers for fun and pretty much all of them have more power and memory than I ever had on a mainframe. Just out of interest I need some blank punch paper tape. Does anyone know of a source?

Bletchley Park was also the place where I and many other telecoms technicians received our early training from BT. So hello to any of you who are still kicking around

Wow! My dad was a lecturer at Wolverhampton Polytechnic in the 70's and I remember seeing the WITCH. So glad its been saved.

Happy Christmas, I'm just having a nostalgic day, and searching for old computers. Look what popped up. Thanks, very well presented.

I can still remember the first computers. The developments have not stopped.

One of my uncles worked on an ENIAC computer in the day. He was excited when he got a commodore 64. He unfortunately passed away in the early 80's but he would have loved to see computers of today!

Very interesting, love seeing these ancestors to the modern computers. The fact that Bletchley Park is still being used as a museum is a surprise and what better place to display these great machines.

I had the pleasure of visiting the National Museum of Computing and Bletchley Park last month. An incredible place!

The ICL 2966 brought back fond memories of school. my friends and I spent many many happy hours mucking around on it before pcs were widely available. to get around the time limit quota assigned to each student, after spending a few hrs on a session, we used to login concurrently from another terminal, logout from the original terminal, then logout out from the newly logged in terminal. the newly logged out terminal overwrote the time usage of the earlier session. we were careful to make sure that our usage was about 80-90% of our weekly quota to avert suspicions.

Hello Again & Thank You So Much For Sending This Link. I Have Several Documentaries About Bletchley Park During The War But You Make It & Post War Advances Even More Interesting. This Made Me Reminisce About My "First", A Tandy RL-1000 With Two, Low-Density (720K) Floppy Drives, No Hard Drive & 512K RAM. A Hayes Compatible 2400 Baud Modem Was Used To Dial-Up Local BBS & To "Expose" My Nostalgia, I Still Have The Copy Of Telix I Used On The Flash Drive I Keep In My Pocket. I Shan't Bore You Any Longer & You Sir, Will Never Bore Me! Thanks Again!

Man, words can't explain how much I really liked this. Thank you Chris for the education you share with the world and I really hope you never get burned out. Cheers

The EDSAC had a memory of 3KB. You'd almost have to look back and laugh knowing that's not even a config file these days. When we look back at storage capacity in the 90's, it wasn't that much. I resurrected a Win 95 Aptiva with Win 98SE not long ago. But what I found strange was it had a 4 Gig HD. Back then you'd expect 1.2 Gig at the most.

Thanks for this. I will have to visit Bletchley again soon. The last time I visited was about 10 years ago, and I can see a lot has changed.

I wish I had a single purpose computer that would press the like button every time for me. I love these vids and it reminds me of old 80's BBC school documentaries that were highly interesting back in the days gone by!

Great information on history of computing. The parking lot resembles the scenes from the movie "Enigma".

These videos on location are really nice, I hope you will do more of them in the future, maybe have some guests or other computer RU-vidrs from the UK.

One of the most interesting video on RU-vid at the time. computer history is fascinating.

Great place. Been there 3 times now. The ICL is very similar to the Honeywell DPS6 that i used to operate in the late 80's.

One of the first computers ever made used no electricity at all, but was completely mechanical. Due to constant breakdowns, the inventor later replaced the mechanical parts with some relay switches. It's a fascinating topic.

Great videos. As a software developer /coder, I find the history of computing incredibly interesting. I released the game called "Charlie the Chav" on the android play store, which I based on old 2d platform games of the 80's. I did it for fun. However, it was done in Java, using very simplistic techniques of OOP that you had no way of getting around, back then. In the old days, you had to code for so many problematic hardware restrictions, such as the type of display unit, the memory, and lack of colour. You had to be very clever, and almost use bodging techniques to accomplish your goal. Now, it's so easy to produce anything. Even a child can develop software. But, what I like to see is this kind of content. We are back to the roots and the guts of our modern cpu. Every bit of hardware we use today comes from this equipment in some way. It should be worshipped. Pure geniuses created this technology.

Wow, this is such a fascinating video. The punched paper tape is so intelligent, love it!

Been there a couple years ago. It was an extraordinary experience. Lots of things to see and activities for kids as well. A whole day well spent.

Hi Chris. Thanks for this "traveling to the past" episode. Very nice.

My first job in computing was kernel dump cracking on P and S series ICL 2900 VME machines (basically what, in later terminology, would be the equivalent of working out what caused a Blue Screen of Death). The ICL 2966 (pronounced "29" "66") in this video was a mid-range S-Series machine. The "big" S-Series machine was the 2988 Superdual. One of the big problems we had with newbie operators was, when they removed the exchangeable discs, they sometimes failed to keep the disc platter perfectly horizontal and the bits would drop off 😉

Hi Christopher, I visited TNMOC in 2019. They have a partially working IBM 1130 which was the first computer I programmed. It was next to the ICL, but I don't think it was there in 2017. Regards.

My mind is blown!!!!! That someone actually made something like those early PC's....... Modern PC's aside... how could ppl come up with that... just WOW!!!!!

In The Netherlands in the late 80s or early 90s as a son visiting my fathers job I visited a building called Coengebouw property of a Dutch Bank and it had similar computers and those large cased disc stacks and machines to drive them as the ones of the ICL 2966

Great stuff Chris! Some of the hardware later in the video I had the opportunity to see as a child in operation where my dad worked... fond memories. xD My dad was an engineer for a contractor company of the Itaipu dam here in Brazil, but before myself coming into existence, he had already worked with valves, punch cards and whatnot. He used to teach classes later in his career so he had samples of the stuff... very unfortunately lost in between moving from one place to another. The oldest PC stuff I still have is probably some floppy disks. I remember that the job place he had into the computer department was an entire building where half of it was the refrigerated server room, and the rest of the building were offices with dumb terminals built litteraly inside desks (custom made desks with a monitor and keyboard built in). They still used floppy disks of the 8 inch size. The server room had a whole bunch of wardrobe sized units, some with spinning taperolls, some for other purposes. The room was refrigerated 24/7, floor had these thick cardboard-like perforated tiles with all the cables running under it. But the thing I remember the most is the printer. It was pretty huge for a child me. xD It opened up like a fridge, and had it's own vacuum cleaner to suck up the bits of paper that came off that perforated paper used for dot matrix printers. All very fascinating.

I visited this museum on my recent trip to Europe, all the way from Australia. I have so many good memories of these computers. thanks for uploading.

I love computing history. It really just brings it back into perspective that these little black boxes we keep in our pocket are truly an amazing accomplishment.

I used to work for the GPO as an engineer back in the 80s and most of the colossus racks psu.displays, plugs and switches we were using still then.

Just watched a RU-vid video on Colossus hosted by the national museum of computing by Chris Shore ( recommended) and stumbled on your video. Another goody, thanks.

Great video Chris! I have worked on valve amplifier equipment in the past and seeing all those valves in their various flip-flop circuits boggles the mind!! Let's think about the heater current needed by these beasts! Valves of this type need a heater, which is an electrical element (the part that is seen glowing in most valves that is heated by an external current) to produce a stream of electrons inside them to make them work. The electron stream formed within the valve by the heater allows another output current to pass, the valve's design providing control of this output current, so making it capable of doing useful work like amplification or binary switching (in the case of these computers). Most valves take between 150mA (0.15A) to 1.5A to power their heaters alone and this wasteful demand represents one of the technology's biggest disadvantages for apart from allowing the valve to work, the heater current contributes nothing to the useful work a valve can do. So, a computer containing around 2,000 valves may end-up consuming between 300 to 3,000 Amps of heater current (unless specialised "high efficiency" valves were used?), with additional power being needed to run the logic/paper tape/indicator etc. circuits as well. This is a lot of power!! Also, all those heaters are going to produce, well, a lot of heat!! I suppose we should be thankful of the development of silicon technology :)

Great video! I visited Bletchley Park and the then joined National Computer Museum back in 2010, now I believe it's a separate entity. Great to see the place again and really like this style of video Chris, can't wait for part two. oh and more of the same please! :)

I know a bit about American computer history and it was great to see the British side. I've heard of the Colossus but never saw a picture of one. I've had the privilege of programming several of the early semiconductor computers in the 1960's (IBM 1627, PDP-1). Part of me still doesn't believe that the Raspberry PI can do so much more than these room-sized machines that led the way to what we take for granted.

Ha - I did my apprenticeship on the prototype ICL 2966 (codename S3) when I worked at West Gorton in Manchester between 1976 and 1980, I helped design one of the boards in the OCP. The very first one went into the Inland Revenue in Dalkeith I recall. Never could get the 64 bit (N64) version working though. Those were good days.

Computing work at Bletchley Park led to LEO, Britain's first commercial computer. Two of the workers there recognised the potential for their former and post-war employer, but they had to visit ENIAC at Princeton to conceal the origin of the idea. If you want the programming manual for EDSAC, read Wilkes, Wheeler and Gill's "archive.org/details/programsforelect00wilk " The Preparation of Programs for an Electronic Digital Computer,

I find tubes (valves) endlessly fascinating. I build high end audio with them, and have built many scratch projects, a few using what are modern computer type tubes.

I spent a good portion of my early career programming the IBM AS/400 mainframe in a language known as RPG. I worked on successors to the AS/400 until 2012 at which point I was unceremoniously laid off. I had to completely reboot my career. I am now an app developer working in much more modern languages. I do sometimes long for the simpler days when there where only a few hundred commands to remember. But overall, I'm probably having more fun.

Good one. Thanks. More history please.

This takes me back a while, great to see the old machines, the ICL was a very popular machine in its day. Having worked for many many years with those hard disks and tape systems its a long way from the mini and modern computers today. Thanks for sharing

Simply wonderful. Good to see you getting out of that green screen and into the real world showing us the wonderful and fascinating history of computers.

I love these old computers. It shows the humble beginnings we've really come from. I love seeing what challenges were overcome with things like core memory being destructive read, and the use of more mechanical parts.

Wade-A-Minnit !! I thought U.S. Battleships had an aiming computer, tied to a gyro, linked to the bridge, before 1944. It had techs running around the computer making sure it was working right. Due to waves the ship would pitch and when the ship was at just the right angle ALLL the guns fired at once to nail the target.

Guess I'm one of few left which had seen a working hard disk drive like the giant disk in your video. It was in a cabinet the size of a large refrigerator, with a massive 5MB capacity. But the disk was of much cruder construction than the one in the video. It had a large plexiglass door discolored and dingy with age. My PC servers actually ran the business side of the facility. They were the smallest devices in the data center and the 'refrigerator' stood behind me. A Xerox Sigma9, iirc. Yes, wikipedia showa a similar drive!

Great bit of history...thanks for sharing it with us!

Chris, you give us such a diverse rage of material, and every bit is enthralling. I have been meaning to visit Bletchley Park for a long time, I didn't realise TNMOC was on the same site ... Like I needed more incentive :-) Got a week off next month so hope to make the trip then.

Very cool video Chris! Really fascinating to see how it all started and came to be... I found the ICL Mainframe to be most interesting and had to smile when i spotted the C64 (my personal "digital origin") and the Commodore PET in the shelves. If you keep going with this kind of subjects, i would love to see a video dedicated to the CRAY machines and its vector processor!

Love the video quality on these old machines nice work

Excellent video! I've been in computers for 40 years but I learned quite a bit from this video. I was surprised at how early "computers" were in operation. I'm also impressed that the reconstructed machines are made with more or less original components -- I'm amazed that the components can be found.

That's an amazing video! I read in the past about few of those computers and it was really fascinating to see some of them "alive" in your video! Please do more of those videos of looking in the past, it is really interesting and your explanations are very good.

Well that was certainly interesting. History is so much more fun to learn about when you can actually see what is being talked about. Of course, being there when history happens can be cool, too. I remember seeing some of the equipment (you showed us) in action when it was cutting edge stuff. I also remember being blown away finding out the wild, wild, crazy storage capacity that those (now ancient) drives had. Little did we know back then... Thanks Chris, for this "field trip" back in time ! How does it feel holding a microphone, a-la field reporter? You do just fine at it.

What a fantastic video Chris! Thoroughly enjoyed watching it - I think I'll have to visit and see them all! Thank You!

When I watch your videos, I often get a feeling of nostalgia. Your shows remind me of the shows from the 80s and early 90s. I love it. :) Keep up the good work!

As an engineer and fan of technological history, it's great seeing beginnings of the computer industry. My first computer was a Commodore 64, so I've seen many improvements over the years. Great memories! When I see these ancient behemoths running though, I can't help but think "Oh my God - the electric bill!" and "How much is this going to add to global warming?!" Last week, I unplugged my 11.5 year old Windows XP machine and made a RaspberryPi 3 my main computer, mainly because I can no longer run an anti-virus program on the PC if I want to do anything else, like check e-mail. The RaspberryPi also takes about 2% of the power the PC does. I will need to get a bigger heatsink for my Pi though. I'm teaching myself Python with it, and when I run my LFSR counter design utility on multiple cores, I get the temperature warning. I've enjoyed your channel for a while now, and just subscribed. Keep up the good work!

Another great video, thank you for the quick tour. I look forward to the video on the smaller machines. If you are looking for ideas for future videos, please consider doing more in-depth historical pieces on some of the machines you covered in this video, I find these histories fascinating. Thanks once again for all of the excellent content that you produce.

+ExplainingComputers / Christopher Congratulations on creating an interesting and historically accurate video. Looking forward to your reviews of old computers.

You make a better documentary than History Channel. I'd listen to you teaching computer history for hours if I could. It's so interesting.

Awesome. I was at the museum on the 4th June. Fantastic display

Love the channel. Your style is deff unique on youtube. Good job.

Awesome video! I remember seeing some early photos of the EDSAC build while back. Looks to of come along nicely.

Wow, although obsolete as hell, the lights in those tubes moving around in there and so quickly looked very cool. I didn't know tubes could be this responsive.

Looking forward to the second part.

One of the Best early Computing docos ive seen. ThankYou Awesome

Great show looking forward to seeing more

The museum is still evolving. They moved the "bombe" round from Bletchley Park and with the Mk1 Collosus, they have them running manned by boffins wearing "tank top" jumpers that give an authentic feel to the age of the machines, while they explain how they work. 5* venue and a must visit sight for anyone with a computer interest " bucket" list.

Awesome video. It is a bit awe inspiring how far we have come in 70 years.

Please do more videos about historic computers.

Interesting stuff. The Zilog Z80 was cool... but as we can see here, proper computers have a wall of flashing lights and spinning reels.

Nice video, reminds us where our wonderful little devices all began.

Thank you for your time to make and upload this video; really well done! :)

back in the 70s I used a computer at Brooklands Technical Collage known as Pegasus with Valve FlipFlops and oscilloscope output....

Fascinating video! I didn't realise that they made so many Colossus computers during the last World War.

Excellent work. Thank you Sir.

Great to see you out and about "on location" Chris! Top-notch content as always!

Can't wait for the PC videos! Great video!

OUTSTANDING video! VERY interesting!!! I look forward to your next one on older PCs. ~Cindy! :)

Brilliant, I'll definitely have to pay a visit to the place.

I saw one of those large ICL drives in Brisbane. The word was that they took 24 hours to get up to speed and that one broke loose and went thru the wall!

Very interesting. Computing history is fascinating - I'll watch and like any such video you post.

Impressive old technology. And the fact the machines run to this day is even more impressive. Germany has a similar museum in Cologne. Very interesting machines they have there. Definitly worth a visit. :) Greetings from Germany.

Thank you for an excellent video.

Excellent video, you are very good at explaining things. Keep up the good work!

In my first IT job, around 2001, I got a look at an old EMC Symmetrix disk array, which was about eight feet tall and held a whopping 1TB of disk space. My, how technology marches on.

Great video as usual ! I remember my first computers the wonderful ZX81, Timex-Sinclair Spectrum, Commodore 64. They were the actual population computer beginning. Thanks

Computing has definitely come a long way. I first started out working with IBM 3032 and ICL 1900s writing code on coding sheets.

Great stuff Chris...can't wait for the next one!...

I wish I had this video when I was writing my paper on this topic yet again another great video

Thanks for the video Chris, very nice.

Very interesting, never knew that computers were so different back then!