Have you ever wondered what the earliest computers were actually like?
I‘m glad you asked! Let me tell you the fascinating story of the Manchester Baby, officially known as the Small-Scale Experimental Machine or SSEM – the world‘s first stored-program electronic digital computer. Understanding how it worked will help you appreciate just how far computing has come since 1948.
When it was unveiled, the SSEM represented a revolutionary achievement – the practical realization of pioneering concepts like random access memory and storing both data and program instructions in the same memory hardware. Both you and I owe a debt to the SSEM‘s creators – people like Frederic Williams, Tom Kilburn and Alan Turing. Their drive to experiment and innovate laid the foundations for modern computing as we know it today!
Overcoming Early Computing Limitations
So what exactly was revolutionary about the SSEM? To answer that, we should first look at what came before it…
In the early 1940s, scientists attempting to build calculating machines hit major bottlenecks. Devices like ENIAC usedvacuum tubes and electrical relays to manually sequence mathematical operations. But ENIAC had a crucial limitation – needing up to three weeks of rewiring by hand to change its programmed instructions!
This is where Williams‘ research on new types of memory using CRT screens proved pivotal…
Introducing the Williams Tube
Williams realized that by controlling an electron beam inside a CRT, he could manipulate charges left on the glass to read and write bits – 1s and 0s! By dedicating an output CRT to display data too, he created the first true random access electrical memory. He called this the Williams Tube.
The Williams Tube changed everything! It meant data no longer had to pass sequentially through fixed function circuits. By using the beam to read and refresh the CRT screen charges, ANY data could now be accessed directly no matter where it was physically stored. And reading or writing to ANY memory location could happen electronically in millionths of a second!
Can you imagine how much this expanded what an electronic computer could now potentially do?
Bringing The Manchester Baby to Life
Williams knew he was onto something big. He started working with Tom Kilburn to build a working computer around his Williams Tube invention at Manchester University. Though neither had built a computer before, the goal was set – to create the world‘s first "stored program electronic computer".
This new type of machine would be revolutionary. It would combine Williams‘ fast electronic memory with the newest concept in computer science – storing instruction programs in the same location as data. This allowed programs to be changed simply by altering what was stored in memory – no rewiring necessary!
It took years of intense engineering effort and plenty of trial and error. But by mid 1948, they had done it – the Small Scale Experimental Machine was born!
Let me walk you through what made the SSEM – soon affectionately dubbed the "Baby" – so groundbreaking:
- Williams Tubes – 1 for main memory, 3 for various data registers and temporary storage
- Vacuum tube circuits – Around 700 implemented the SSEM‘s logic functions
- 32-bit binary word size – Huge for the time! Gave 32 binary digits (1s or 0s) to represent instructions and data
- Limited instruction set – Just 7 operations like subtraction, conditional jumps and halts
- Clock speed – 1.2 millisecond cycle time. Tiny by modern standards but amazingly fast electronically for 1948!
Trust me, this was an incredibly advanced computer for its era. Even just the ability to automatically run programs without requiring hardware changes was astounding.
Now let‘s look at what programs on this pioneering system were actually like…
"1,2,3 Testing!" – The SSEM‘s First Program
With the Manchester Baby built, the next step was letting it run some programs! Tom Kilburn developed the first to really prove what was possible:
The goal was factorizing numbers by trying every possible factor sequentially. This let them string together huge sequences of:
- Repeated subtractions
- Conditional jumps based on the result
- Memory look-ups to get the next number to check
It was mathematically simple but a revolutionary test of the SSEM‘s capabilities – could it reliably sequence thousands of stored program instructions without failure?
On June 21st 1948, they had their answer. The program successfully factorized numbers through over a million operations across 52 minutes! The stored program electronic computer had arrived – calculating like an electronic brain by working through long instruction sequences from its Williams Tube memory!
The Dawn of a Computing Revolution
You‘re likely eager to know what happened next! I‘m happy to tell you the SSEM‘s success sparked enormous progress over the following years:
- Expanded Manchester computers were built – notably the Manchester Mark 1 which ran a number of university research efforts
- Commercial spin-off Ferranti Mark 1 became the world‘s first computer available for sale in 1951 – kickstarting the British computing industry
Perhaps most significantly, the concepts proven by the SSEM defined the computing paradigm that every digital device since owes its origins to – including the one you‘re reading this on right now!
So hopefully you can now appreciate why the SSEM represented such a huge leap forwards. It pioneered implementations of key concepts like random access memory, storing programs digitally and sequential operation. Most importantly, it proved what was capable when engineers dared to think creatively.
The next time your laptop or phone frustrates you, remember how comparatively simple computing started off! Given how rapidly innovation took off in the 50 years since the Baby, who knows where we might be by 2050? Understanding pioneering technology like the SSEM helps inspire the next generation of computer engineers to push boundaries.
I hope this glimpse back in history was as fascinating for you as it was for me! Let me know if you have any other questions.
