What is 64 bit? Beginners' guide

2006-Aug-05 | Tags: 32or64learn

Start64!There are people who can hardly wait to upgrade to it, while others already fear its novelty. There are people who expect an improvement in quality, while others do not make full use even of the existing capacities. There are people who use technical aspects as arguments, while others think that those mean-spirited marketing people have cooked up something again to get the money out of their pockets. Who is right? Who will benefit from the 64-bit technology, and who will not? After all, what is 64-bit?

A bit is the basic unit of information. It can hold one of two values: 0 or 1. It is a digital, i.e. a two-state, quantity: it can be either one or zero, or in other words: yes or no. This is exactly how digital electronic circuits work: the current is either present at certain points of the circuit, or they are not. Of course, such simple circuits can be used to build highly complicated systems. E.g. even a microprocessor can be constructed using just some of these basic circuits. A microprocessor is called the central processing unit (CPU). Advanced microprocessors consist of 200-300 million basic elements today.

Intel 4004, the first 4 bit CPU
Intel 4004, the first 4 bit CPU

The first CPU was a 4-bit processor. This means that it could process 4 bits of information simultaneously. If we put 4 bits next to each other, and each bit can hold a value of 0 or 1, then we can create a total of 16 different value combinations. These combinations can be viewed as values expressed in the binary number system. Every such processing unit can take a value between 0 and 15 expressed in our good old decimal number system. So the early 4-bit processors were capable of expressing the values of the usual digits from 0 to 9. What is more, more of these can be put in a row, and then we can express any high value number with them. The calculators of the 70s, which were capable of performing the four basic arithmetical operations, contained such early microprocessors.


8 bit

In the meanwhile, technology went through continuous development, and more and more advanced new microprocessors containing an increasing number of basic circuits were constructed. The 80s saw the thriving of the 8 bit technology. Legendary 8 bit computers were built. Many remember the Commodore 64 and Sinclair Spectrum personal computers.
These could be used to perform serious tasks.

Commodore 64
Commodore 64


Certainly, the most complicated task was playing games. A game is a fairly complicated task from a technical point of view. These were the computers for which the first games relying on more advanced graphical capabilities were released. These games already had serious business prospects. Perhaps games also contributed to the huge development which followed and is continuing to this day. The game market is a determining factor today. It is enough to think about video cards and everybody will understand what I mean by that. Basically, 8-bit microprocessors are constructed similarly to 4 bit ones. The difference is that here the system already considers 8-bit information as one unit, and such a unit can already assume 256 different values. The 8-bit unit has become wide-spread, and they named the 8-bit value group a byte. Such a wide value range is sufficient to complete a large number of tasks. The graphical resolution of Commodore 64 computers could be set to 200x320 or 200x160 pixels. The 8-bit processing allowed to specify the co-ordinates of any pixel in a single processing unit. From a certain point of view, those days saw a revolution in information technology. Looking back from today, the 64 kbyte memory of the Commodore 64 was tiny, but that was all the memory capacity that was available for the graphics, the music and the program code of games. At present an average size jpg image file, or a Word document is much larger than 64 kbyte. This period is called the era of artistic programming.


16 bit

The 16-bit era started in the middle of the 80s. At the time this technology was available to few people because – due to the international political situation – Western interest groups set up the so-called COCOM list , which was aimed at preventing Communist countries from getting advanced technical equipment. 16-bit computers represented advanced technology as they could be used to build military computer systems, therefore their sale to Communist countries was prohibited. The main point is that these computers had 16-bit microprocessors and could handle 16 bits of information simultaneously. This equals to 65 536 different combinations per processing units. These capabilities allowed the solution of highly complicated calculations and made games look much more attractive and run faster. The computers of this category: Atari , Amiga , Macintosh and the PC .

Amiga 1200
Amiga 1200


The 16-bit systems remained in use for a comparatively longer period due to the DOS and early Windows operating systems. Computers had 32-bit CPUs for years when 16-bit systems were still dominating the IT market due to the operating systems in use. Which means that at that time we already had a certain overlap between technical capabilities and their implementation.


32-bit results in 64-bit

32-bit systems were gradually gaining ground through running newer and newer Windows releases. 32-bit operating systems could often be installed on the existing hardware since the underlying technology used in the latter was actually 32-bit, but was used as if it were 16-bit. This era started a couple of years ago, and the larger part of today’s systems use 32-bit technology. This means that the microprocessor installed in the computer can process 32 bits of information simultaneously. This equals to 65 536 x 65 536 different combinations per processing units. Which is more than 4 billion. 32-bit systems are capable of processing sound and video files. This is considered to be everyday use of computers today. Well, of course, not only the number of simultaneously processed bits increased but so did the speed of processing. The management of, for example, divx coded films requires a tremendous calculation capacity, and yet, this is not a problem for any average computer today. By using 32-bit systems, we can apparently handle any informatics tasks related to our hearing and sight (audiovisual tasks). If it is so, why do we need the 64-bit technology?

Now you will learn why we need the 64 bit technology
Now you will learn why we need the 64 bit technology

32-bit systems have a basic problem. Every part of a 32-bit microprocessor relies on the 32-bit technology. That is, not only the quantity of simultaneously managed information equals to 32 bits, but the system also handles the memory in 32-bit units (this operation is called memory addressing). If you install each and every update patch on your Windows XP operating system, it will almost take 256 MB of the memory. If you also want to use professionally set up firewall and anti-virus programs, that memory capacity will be too little, and your system will slow down considerably. The conclusion: convenient and safe solution of an average task requires a memory capacity of 512 MB today. In the case of gamers even 1 GB of memory is not considered to be too much. With the release of Windows Vista, this memory requirement will double because the operating system, which includes a great number of new features, requires 512 MB memory by default. If we install a firewall and an anti-virus program, even that will not suffice, which means that providing a safe and convenient environment for doing some ordinary work with the computer will require 1 GB of memory, and more than that (about 1.5-2 GB) for gamers. And with that, we have come to big issue: 32-bit processors cannot address more than 4 GB of memory due to the above-mentioned, somewhat more than 4 billion available combinations. The average requirements of today are close to that limit. Therefore we can state that the 32-bit system has reached its limits from a technical point of view.


64 bit

The 32-bit system will obviously be sufficient for ordinary use for a long time (which means not more than a couple of years in informatics), but in other circumstances it is already inadequate, and maintaining continuity and compatibility while migrating to this new technology is of utmost importance. This is what made Windows the dominating operating system on the PC: it always complies with these requirements. Continuing this tradition, the Windows Vista operating system, which is expected to be released this year, will be available both in 32-bit and 64-bit versions. A new computer is likely to be based on the 64-bit technology today, even if it is used as a 32-bit machine. The 64-bit technology has been around for 15 years and used in corporate systems. As a result of AMD developments, this technology became available also for home computers some years ago. 

What is 64 bit? Beginners’ guide

In the beginning only certain Linux distributions were capable of properly using 64-bit systems, but today we already have the 64-bit edition of the Windows XP operating system, and Intel also began to market its own 64-bit processors. In theory, there is not anything that would hinder the spreading of the 64-bit technology. But there are practical obstacles. 64-bit Windows releases offer software compatibility with the 32-bit versions. It is important to note here that this means compatibility only with user-level programs. You should not forget that a 64-bit Windows is completely different from the 32-bit versions, that is, the drivers needed for the installed devices are completely different, just like the anti-virus and firewall programs. And the range of these is rather limited at present .

We have taken into account the technical aspects so far. It is worth mentioning here that there are other aspects, too. Economic interests are very strong and end-users have special needs and habits. Users, technical possibilities and economic interests joining in declared and undeclared associations form the world of informatics both individually and as a combined force. 



 Development was uninterrupted from the 4-bit and to the 32-bit technology. The previous and the next generation generally co-existed even for a longer period of time. The 64-bit technology departs from that path because, now for the first time, it is a technical necessity to migrate to 64-bit. 

It is important to emphasize it again that here we are talking about informatics for which you can buy parts in any ordinary shop selling computer parts, i.e. about home and office computers, laptops and workstations. Every computer user is familiar with this category. Considering the number of computers, this is the most populous group but not the only one. In the corporate informatics segment 64-bit systems have been available for 15 years now . Microsoft develops certain server operating systems (also belonging to the Windows family) only in 64-bit versions. In the corporate and server segments the requirements have already reached or even exceeded the capacities of the 32-bit technology. 

What is 64 bit? Beginners’ guide

A memory capacity of 4 GB may seem more than enough in the eyes of a home or office computer user. Some years ago every user dreamt of having 128 MB memory capacity installed in their computer, now we have 256 MB installed on an average video card. Windows XP will run safely after professional installation (anti-virus, firewall etc.) if the computer has at least 512 MB of memory. Gamers quite often have 1 GB installed. Windows Vista expected to be released in the near future will double these values. According to this, we have already reached the upper limit of the 32 bit technology in terms of capacities. Remaining reserves can only support a continuous migration to the new technology.

And this means that the memory needs of application segments increase by the year. This trend is unlikely to end. While expanding the memory capacity of one’s computer used to be a matter of money, today it has technical limits even on the level of everyday needs. All of us are affected by the migration to 64 bit. This is not a question of viewpoints any longer, but a consequence of technical necessity.