- Computers & Software
Classification of Computers According to Data Processing: Analog, Digital and Hybrid Computers
Ever since they came into our lives, computers have been designed to process raw and other data into useful information. In order to implement this daunting task, the brains behind processing innovations have used two major generations of signal technologies to get the job done: analog and digital signals. Somewhere in between, they have fiddled with hybrid computers in an attempt to unite the two signals above.
Analog computer signals were the first to see the light of day but have since been superseded by digital implementations. It is therefore correct to say that the early computers and contraptions made in the beginning of the 20th Century were analog, whereas computers manufactured at the close of the 20th Century through to the 21st Century have largely been digital.
The transition from analog to digital technologies was made possible because of the need to accomplish tasks faster, efficiently and with less clutter.
One example where technology had to change was in voice communication. While telephony was simple to use during the age of analog installations, it was hampered because it was expensive for long distance calls and there was limited scalability.
Contemporary digital telephony, however, provides cheaper call rates, has better call transmission quality and improved scalability.
1: Analog Computers
Humans perceive the world in analog, which explains why every bit of info we see, speak and hear is transmitted in continuous form. This infinite stream of information adds up to what we understand as analog signals.
Analog signals take advantage of mechanical, electrical and hydraulic quantities of nature to simulate problems to be solved.
Unlike contemporary computers which can be used for various computing purposes at home and office, analog computers were used for industrial purposes to measure parameters that vary continuously.
Analog computers were and can be used to measure the following signal types:
Using the analog clock as a simple analogy, the minute and hour dials are constantly on the move and just by looking at the minute hand, you can visually measure time gone by or time to come without having to cycle between digits 0 to 9 as is in digital clocks.
Analog signals are continuous variables and take place simultaneously, continuously and in real-time without the need of additional computations and tools on the sides. A running analog computation process is an end in itself.
When recording analog data, the output sequence is recorded in continuous rather than binary signals. Analog computers are solution oriented towards differential equations where time is the most important variable, and since they produce only continuous signals, the computed outputs do not use word length as a criteria for computation. Usually, computation and output happen simultaneously.
Analog computers were actually the first in a series of what culminated to current breeds of supercomputers and personal computers. They were used to design and test various kinds of aircraft, ICBM (Intercontinental ballistic missiles) and in numerous industrial installations.Their popularity gradually ebbed in the 1950s and 1960s as digital computers became computers of choice.
Until today, engineering and artistic research fraternity prefer using simulation to model experiments during design stages of industrial products, and the scientists in the 50s-60s turned to analog systems to bring their ideas to life.
For example, in trying to perfect the suspension system in a car design, analog systems could be used to simulate and thereby provide engineers better designs of pressure resistant suspensions. As long as experimental environments could be explained by mathematical formulae, they also could be simulated along analog computers.
Simply put, as long as experimental environments could be explained by mathematical formulae, they also could be simulated using analog models.
Analog computers have disappeared from mainstream establishments and can only be found in select research, universities and industrial facilities, and as experimental models for computer geeks.
Electronic enthusiasts still fiddle around with challenges of analog electronics because it measures real-time data to information as opposed to internal data processing in digital systems.
Analog devices are also remembered as experimental contraptions and were far from achieving what digital systems have achieved by far. Despite championing parallel processing in ways better than digital systems, they lagged behind when it came usability for ordinary users. On the contrary, digital signals from digital devices have proved easy to use and resultant data easy to manipulate and store.
This does not mean that analog devices and memorabilia are foregone in our history. It is obvious they played an important role until there arose better computation methods and the craze over personal computers. Everywhere you turn, you will find digital gadgets such as computers, digital cameras, smartphones, video games, name it.
Despite the disparities between the two technologies, it is probably safe to write that society has lived and will continue to live both analog and digital lives.
Analog Output Signals
When engineers were running tasks on an analog computer, it simulated the real world by running specified formulas and output could be read in electric voltages and various kinds of mechanical motions.
Traditional analog computers did not necessarily need storage resources as output because computation from analog computer could be read and used real-time.
Examples of Analog Devices and Computers
- Slide rule
- Tide Predictor
- Analog clock
- Nomogram: a graphical calculating device
- Operational amplifier
- Mechanical Integrator
- Electric integrators that solve partial differential equations
- Norden bombsight
- Oscilloscope: used to measure electronic instrument voltage against time.
- MONIAC (Monetary National Income Analogue Computer): built in New Zealand in 1949 to model UK national economic process.
- Water Integrator Computer: Built in Russia in 1936 to solve differential equations
Have you used an analog computer before? If so, tell us your experience in comments
2: Digital Computers
Digital computers as the word suggest work by manipulating binary digits which are represented in numerals and non-numeric letters and symbols. They discreetly estimate electric data signals using zeros and ones. Unlike analog computers which measure data to information in an infinite form, digital computers operate by estimating data input and output using the 0 and 1 binary mode or discrete ON and OFF electric signals.
Digital computers are capable of delivering more accurate data than analog computers. They manipulate logical operations and arithmetic operations like multiplication, addition, subtraction, and division.
In layman’s language, a digital computer is designed to process arithmetic or logical calculations automatically using binary digits. Nearly all computer devices today are digital, meaning that they use binary numbers to manipulate data signals in two major states: 0 (zero) and 1 (one).
Some of the advantages of digital computers over analog computers include versatility and accuracy and they are easily re-programmable.
Also, most information today is stored digitally in and out of the computer. If also you wish to transfer analog files like audiovisual recordings from old analog video tapes into your computer for purposes of storage and editing, you can use analog to digital converters (ADC) for this purpose.
Differences Between Analog and Digital Devices
The major difference between digital and analog computers is in the manner in which they handle data. While digital computers use binary language in order to accurately effect computation, analog computers handle continuous data such as voltage changes and temperature fluctuations to output its computation.
Work on continuous values
Work on discreet values
Measure quantities like speed and temperature
Solve mathematical problems like addition and subtraction
Preferable in engineering and scientific fields
Used by all and in all sectors of society
Special purpose computers
PCs are general purpose computers
May have no memory
Must have memory in order to operate
Use carefully written lists of instructions
Can connect different sub-systems together electrically with patch cables
Produce numbers as output
Output voltage signals, and has sets of analog meters and oscilloscopes to display the voltages
Vary in size from tiny contraptions, desktop size to multi rack equipment
Vary from tiny embedded systems to room-sized server systems
Storage is difficult because they use continuous signals
Numeric, discrete nature of digital computers makes data storage simple
3: Hybrid Computers
Hybrid computers are a combination of favored features of analog and digital computers. This should be the computer of choice if the user has to process both continuous and discrete data.
From a perspective point of view, a hybrid computer has the speed of an analog computer and the accuracy and memory of a digital computer.
For example, an analog device could be used to measure patient blood pressure and temperature in a medical facility and derived data is converted into meaningful digital data.
Most of the time, a hybrid computer is designed for specialized assignments. They are used in sensitive military installations and important buildings to monitor special activities and radar functionalities.