Computer History

Uninformed researchers of computer (computador) history would probably note the first computer in the mid 1930`s. In reality, this history dates nearly 2000 years ago with the invention of the abacus where the user programmed beads using formulated constructs.

Although many historians caution against the use of the word computer (computador) except to define 20th century computers, a broader understanding illuminates an instrument designed by a Frenchman and which functioned as a calculator and was designed for a tax collector in the 1600`s. Improvements to this calculator continued through the 19th century.

Similar work was underway in England and with the support of the government a `mechanical` calculator was invented. It was powered by steam and supported a fixed program for its use. This calculator went through many changes until an automatic calculator was invented. Following this flurry of discovery and invention, little changed until the early 1900`s when detailed mechanical and transportation work required complex mathematical calculations (especially calculus).

Two Census Bureau workers began to look for a means of accurately calculating information. They conceived the idea of a punch card which would be inserted into the computer (computador), read, and stored. The greatest advantage of these still slow moving machines was the ability to store large amounts of information with ease and accuracy.

The early 1940`s and the imminent World War, brought the military into the computer era (computador). New weapons requiring computer technology for effectiveness, were needed, designed and produced. These were large floor model machines and utilized the floor space of an average one family home (about 2,000 square feet). One independent computer (computador) was not adequate and a means was found to link computers which produced a more accurate and clear channel of information. These devices were not only cumbersome but they required rewiring and rechanneling for each program. Greater inventions were in progress. These new computers (computador) would be equipped with memory capacity and worker faster than any in existence at the time.

In 1947, the first modern programmable computers (computador) were designed. They contained RAM (Random Access Memory) and made it possible to access information in seconds. This technology continued to be tested and improved into the 1950`s when magnetic core memory and a transistor circuit element were discovered. These increased the memory capacity and functionality of the computers (computador). On the down side the cost to operate these machines was astronomical. By nearly sheer determination alone, these devices evolved into amazing machines able to work with a number of programs simultaneously while giving the impression that only one program was in use.

As recently as the 1960`s computers (computador) were more available and the price had become nearly reasonable for businesses. Their use however, was confined mostly to mathematically based operations such as billing, accounting, and payroll. One of the major purchasers of these devices was hospitals which stored date from patients, inventory, billing, treatments, and the like.

By the 1980`s smaller individual computers (computador) were being produced. Technology continued to astound the general public as the microchip came into existence permitting personal computers to be sold with accompanying program disks for downloading. A glance around most medium to large companies would reveal many desk top computers in use.

It would be impossible to track the history of computers (computador) without acknowledging Apple Computer and IBM for their leading edge and evolving technology. Radio Shack coupled with Apple Computer (computador) produced video games for the computer (a move from the arcade).

The ability for businesses and individuals to access the worldwide web gave birth to new and innovative marketing and communication with inquirers and/or clients. Today it is inconceivable that one attempt to research something on line and not find multiple references there. The momentum has only continued to mount and new upgrades are available nearly by the day.

This article is under GNU FDL license and can be distributed without any previous authorization from the author. However the author's name and all the URLs (links) mentioned in the article and biography must be kept.

Uninformed researchers of computer (computador) history would probably note the first computer in the mid 1930`s. In reality, this history dates nearly 2000 years ago with the invention of the abacus where the user programmed beads using formulated constructs.

Although many historians caution against the use of the word computer (computador) except to define 20th century computers, a broader understanding illuminates an instrument designed by a Frenchman and which functioned as a calculator and was designed for a tax collector in the 1600`s. Improvements to this calculator continued through the 19th century.

Similar work was underway in England and with the support of the government a `mechanical` calculator was invented. It was powered by steam and supported a fixed program for its use. This calculator went through many changes until an automatic calculator was invented. Following this flurry of discovery and invention, little changed until the early 1900`s when detailed mechanical and transportation work required complex mathematical calculations (especially calculus).

Two Census Bureau workers began to look for a means of accurately calculating information. They conceived the idea of a punch card which would be inserted into the computer (computador), read, and stored. The greatest advantage of these still slow moving machines was the ability to store large amounts of information with ease and accuracy.

The early 1940`s and the imminent World War, brought the military into the computer era (computador). New weapons requiring computer technology for effectiveness, were needed, designed and produced. These were large floor model machines and utilized the floor space of an average one family home (about 2,000 square feet). One independent computer (computador) was not adequate and a means was found to link computers which produced a more accurate and clear channel of information. These devices were not only cumbersome but they required rewiring and rechanneling for each program. Greater inventions were in progress. These new computers (computador) would be equipped with memory capacity and worker faster than any in existence at the time.

In 1947, the first modern programmable computers (computador) were designed. They contained RAM (Random Access Memory) and made it possible to access information in seconds. This technology continued to be tested and improved into the 1950`s when magnetic core memory and a transistor circuit element were discovered. These increased the memory capacity and functionality of the computers (computador). On the down side the cost to operate these machines was astronomical. By nearly sheer determination alone, these devices evolved into amazing machines able to work with a number of programs simultaneously while giving the impression that only one program was in use.

As recently as the 1960`s computers (computador) were more available and the price had become nearly reasonable for businesses. Their use however, was confined mostly to mathematically based operations such as billing, accounting, and payroll. One of the major purchasers of these devices was hospitals which stored date from patients, inventory, billing, treatments, and the like.

By the 1980`s smaller individual computers (computador) were being produced. Technology continued to astound the general public as the microchip came into existence permitting personal computers to be sold with accompanying program disks for downloading. A glance around most medium to large companies would reveal many desk top computers in use.

It would be impossible to track the history of computers (computador) without acknowledging Apple Computer and IBM for their leading edge and evolving technology. Radio Shack coupled with Apple Computer (computador) produced video games for the computer (a move from the arcade).

The ability for businesses and individuals to access the worldwide web gave birth to new and innovative marketing and communication with inquirers and/or clients. Today it is inconceivable that one attempt to research something on line and not find multiple references there. The momentum has only continued to mount and new upgrades are available nearly by the day.

This article is under GNU FDL license and can be distributed without any previous authorization from the author. However the author's name and all the URLs (links) mentioned in the article and biography must be kept.

We have discussed, in the History of the Computer series, the operation and development of the computer and changes in the technology. The other components of a computer system, the peripherals, or external devices have also changed over the years. Drums have more or less disappeared, as have paper tape and punch cards. Monitors have appeared, replacing teletype machines as a way of operator communication.

PAPER TAPE

Mechanical paper tape readers used initially were too slow for the computer, and the sprocket hole was used to gate the data from the tape, read by photo-electric cells aligned across the tape path, to an input register, from where it was decoded and transferred to system memory. This required 9 sensors, one for each bit, and one for the sprocket. The reader pulled the tape past the sensors by holding it against a constant speed motor driven capstan with a rubber pinch roll, energised by a solenoid.

The paper tape punch was still mechanical but could punch much faster than a typewriter driven punch. Maybe today we could use lasers to punch the holes, but we're past that now!

PUNCH CARDS

A medium used since the 1800s was adapted for use with computers, the punch card. These were accurately specified in terms of dimension and thickness and where the holes were punched. They had to be capable of being read at high speed. A common tool of the computer engineer was a 'card gauge'. A punched card could be placed on the gauge, and checked for accuracy. Thickness was important as the reader was set to take one card at a time, not 2. A box of cards, stored in a non air-conditioned environment was likely to be out of tolerance, and would be impossible to use.

A program or data to be loaded into a computer would first be punched into the card by a key punch machine, an operator would type the data, one character at a time into the keyboard, and the machine would punch the appropriate pattern on the card. The deck of cards punched out could be fed through an 'interpreter', which would print the encoded information along the top of the card. Later, the card punch would incorporate an interpreter.

The cards to be read into the computer would be stacked in a card reader, which read the data on the card in a similar way to the paper tape reader, with sensors. Card readers, along with everything else improved in speed reaching 2000 cards per minute. 'Everything else' included crashes, where a card got stuck in the read path. Some machines would stop dead, damaging a couple of cards, others were more spectacular, and sprayed them all over the computer room. A card punch was a standard computer peripheral device, and would punch the cards a row at a time, or a column at a time. This electro-mechanical beast typically operated at 100 cards per minute. In Part 2 we look at printers.

In previous articles in the History of the Computer series we discussed machine codes, programs, and memories. We also mentioned that many types of memory are volatile, that is, if we remove power, the memory loses it's data. So how did the data in your computer right now get there? Is this like the Big Bang theory of the universe? Did it just appear? If you've ever had to reload an operating system, plus all the other programs you use, you'll know it's no simple task to get it onto the disk! After that you have to get it into memory - every time you 'boot'!

What do we mean by boot? My old instructor on my first computer engineering course called it a 'bootstrap binary loader'. That's a clue! The term is said to have originated from fictitious tales of a German character you may have heard of, Baron von Munchhausen.

His exploits were serialised in comic strips and the like, along with Dick Tracey etc. One famous tale had him riding a cannonball and, deciding it wasn't such a good idea, swapping to an enemy cannonball going in the opposite direction, to return to his side.

The outrageous tale we are concerned with here refers to the time when he fell into a swamp, but was able to save himself by pulling himself out by his hair. Later versions of this tale had him lifting himself up by his own bootstraps. This expression 'pulling yourself up by your own bootstraps' was common at one time. It meant to get yourself out of your own problems.

All this doesn't have much to do with computers, but it describes the way they start up!

Early digital computers were loaded from paper tape or punch cards, later magnetic tape, and then disk. You may know that before Windows there was DOS, which refers to a Disk-based Operating System.

On a mainframe computer there is an operating system, which acts as an interface between the machine and the user. This OS is variously known as the 'Exec' (Executive) or 'MCP' (Master Control Program) etc. dependent on the proprietary computer system in use. (New employees were surprised to learn that they had to 'boot the exec every morning' - a high turnover of CEOs?). This is roughly equivalent to the Windows or Linux operating system on your PC.

The OS handles all input from users, allocates time slices and prioritises jobs, controls print jobs, allocates mass storage, etc. When you talk to the computer, it only hears what the OS tells it! The OS can talk to the computer in its own language. So the OS must be capable of loading itself from a disk or tape into memory.

To do this, we have a system whereby a block of data, known as a 'boot block', and located at the very first block of a paper tape, or magnetic tape, or address 00 on a disk, is read into memory at location zero onwards. This 'boot command' is usually a Read instruction from address 00 on device 00.

The data, contained in the boot block, loads the necessary buffer areas to handle an I/O transfer of data in the 'reserved' area of memory etc., ready for communication with the boot device, for example the disk containing the OS. Having set up all the necessary buffers, the computer reads and executes the instructions from 00 onwards. These instructions, just loaded from the disk boot block, finish the setup process.

The final instruction from the boot block is a read command to the disk, to load the rest of the data for the OS. This data overwrites the boot block data in memory with the normal data required for running the system. Once the data is loaded the OS can start operations.

It must initialise all the subsystems, and check what resources are available. It needs to know how much memory there is, what data is available on mass storage, what network resources are available, etc. To do this it may refer to a previous configuration, which it then compares to what it can see now. Alternatively, for a 'clean' boot it checks what resources it has and works from there.

We have seen, in the History of the Computer series, how machine code is used to operate a computer so that it can use 1s and 0s to interpret a program's intentions. But what about a code for human communication with the computer? We can variously write and read to and from different media, such as paper tape, magnetic tape, disk or teletype, but we need some means of converting English (or another language) into a form which can be carried on these media.

You may recall the old Western movies where the James gang shoot the telegraph operator so he can't call the Marshall for help. Or the movies about the '29 Wall St crash where the tycoon reads the bad news on the ticker tape and promptly leaps out of 32nd floor window. Both of these are early examples of a code being used on a medium. In this case morse code on the telegraph, and an analog code produced from a keyboard at the transmitting point, also sent by telegraph. The ticker tape, so called because of the noise made by the printing mechanism, carried the Stock Code, as used in today's stock market, and a quote.

A later code used for paper tape, the baudot code, named after the French inventor, Baudot, was a five bit code, punched across the tape, giving a 1s and 0s pattern to make up the 26 letters of the alphabet. The tape was an inch wide and came on big reels. A sprocket hole was punched in the tape so that it could be moved through the reader.

As we know from our look at binary codes, 5 bits will give us a total of 31 characters (1+2+4+8+16) plus zero. With 26 being used for the English alphabet, the other characters are used for Carriage Return, Line Feed, etc. These are needed to operate the typewriter used to print out the information. Another character, Bel was used to ring a bell on the typewriter to alert the operator.

Later a Shift character was incorporated, similar to the Shift key on a typewriter, so that following characters would indicate numbers. Another shift code would switch back to letters. This Baudot Code was used on teletype machines to transmit data from one location to another. This was later accomplished by first punching the tape, and then transmitting it by feeding it through a 'high speed' reader. These speeds were gradually increased as the technology improved, and were generally expressed as the 'Baud Rate', roughly equivalent to bits per second, also named after Baudot. Most problems came from punching errors and synchronising transmitter and receiver.

In part 2 we look at how codes are used in computers.

We have made reference to computer memory several times in this series, history of the computer, now it is time to look at how it has developed, and is still developing. A look at a block diagram of a modern PC will show how the memory is central to the way a computer operates. Everything passes through it. Many would say the processor, or CPU is the most important part, but you can see that everything depends on the memory. The easiest way to improve the performance of a computer is to add more memory.

The layout of the PC is much the same as the original digital computers. They didn't have monitors, or optical disks, but they had control panels, a teletype, for operator communication, and paper tapes, punch cards, magnetic tapes and drums for data storage. The invention of the core memory in the late 1940s really made the computer a practical, general purpose, commercial reality.

What do we mean by memory? An obvious answer would be a component that remembers something to be used later. Does this mean like a hard drive? This is certainly something you can use to remember what you 'told' it. However, in computer talk, this would be called 'mass storage'. By this we imply a very large capacity in comparison to the 'core' memory, which is the basis of the computer. Also mass storage is normally much slower to access, as it is primarily mechanical.

So what we mean by 'computer memory' is a storage medium which can be accessed very quickly, and at any particular location, or address. This is the meaning of a term you have probably heard - 'RAM' - which is an abbreviation of Random Access Memory. Another term you may have heard, I used in the previous paragraph, 'core' memory. Core has a very appropriate meaning of the 'center' of the computer, like, for example, an apple core or the earth's core (as featured in many a science fiction movie!).

However the origin of 'core' is a reference to the type of memory used in early digital computers. The cores were rings of ferrite material, similar to the built-in antenna used in your AM radio. The ring was about the size of a small shirt collar button, and shaped like a donut! Each core represented one bit, so you would have needed 16 of these to form 1 byte. We will be looking at 6 bit characters. At the time 6, 7, or 8 bit characters were the standard, and normally included a 'Parity' bit.

Parity is a form of error checking, we will be looking at that in another article. For the moment we will just say that 'Odd Parity' means that the 6 bits in a character, plus the parity bit, must add up to an odd number of '1' bits. If there are an even number of 1 bits, as in the binary 000101 (decimal 5), we must make the parity bit=1 (1000101). If there is an odd number of bits, as in binary 000111 (decimal 7), we make the parity bit=0 (0000111). Now when we write a '7' to memory we also write a parity bit of 0. When we read it back, we check for an odd number of bits in the data we read out. If the parity check fails, we have a problem.

In Part 2 we will look at the physical layout of the core memory.

Uninformed researchers of computer (computador) history would probably note the first computer in the mid 1930`s. In reality, this history dates nearly 2000 years ago with the invention of the abacus where the user programmed beads using formulated constructs.

Although many historians caution against the use of the word computer (computador) except to define 20th century computers, a broader understanding illuminates an instrument designed by a Frenchman and which functioned as a calculator and was designed for a tax collector in the 1600`s. Improvements to this calculator continued through the 19th century.

Similar work was underway in England and with the support of the government a `mechanical` calculator was invented. It was powered by steam and supported a fixed program for its use. This calculator went through many changes until an automatic calculator was invented. Following this flurry of discovery and invention, little changed until the early 1900`s when detailed mechanical and transportation work required complex mathematical calculations (especially calculus).

Two Census Bureau workers began to look for a means of accurately calculating information. They conceived the idea of a punch card which would be inserted into the computer (computador), read, and stored. The greatest advantage of these still slow moving machines was the ability to store large amounts of information with ease and accuracy.

The early 1940`s and the imminent World War, brought the military into the computer era (computador). New weapons requiring computer technology for effectiveness, were needed, designed and produced. These were large floor model machines and utilized the floor space of an average one family home (about 2,000 square feet). One independent computer (computador) was not adequate and a means was found to link computers which produced a more accurate and clear channel of information. These devices were not only cumbersome but they required rewiring and rechanneling for each program. Greater inventions were in progress. These new computers (computador) would be equipped with memory capacity and worker faster than any in existence at the time.

In 1947, the first modern programmable computers (computador) were designed. They contained RAM (Random Access Memory) and made it possible to access information in seconds. This technology continued to be tested and improved into the 1950`s when magnetic core memory and a transistor circuit element were discovered. These increased the memory capacity and functionality of the computers (computador). On the down side the cost to operate these machines was astronomical. By nearly sheer determination alone, these devices evolved into amazing machines able to work with a number of programs simultaneously while giving the impression that only one program was in use.

As recently as the 1960`s computers (computador) were more available and the price had become nearly reasonable for businesses. Their use however, was confined mostly to mathematically based operations such as billing, accounting, and payroll. One of the major purchasers of these devices was hospitals which stored date from patients, inventory, billing, treatments, and the like.

By the 1980`s smaller individual computers (computador) were being produced. Technology continued to astound the general public as the microchip came into existence permitting personal computers to be sold with accompanying program disks for downloading. A glance around most medium to large companies would reveal many desk top computers in use.

It would be impossible to track the history of computers (computador) without acknowledging Apple Computer and IBM for their leading edge and evolving technology. Radio Shack coupled with Apple Computer (computador) produced video games for the computer (a move from the arcade).

The ability for businesses and individuals to access the worldwide web gave birth to new and innovative marketing and communication with inquirers and/or clients. Today it is inconceivable that one attempt to research something on line and not find multiple references there. The momentum has only continued to mount and new upgrades are available nearly by the day.

This article is under GNU FDL license and can be distributed without any previous authorization from the author. However the author's name and all the URLs (links) mentioned in the article and biography must be kept.