Understanding Computer Basics: Units, Software, and OS
Units of Measurement in Computing
The nature of information is analog, meaning signals are continuous in time. In contrast, information on computers is represented by digits, the language of computers. In everyday life, we express information using a given language and a decimal number system. Computer circuitry recognizes two types of digital electrical signals: the presence of a signal, equivalent to 1, and the absence of a signal, 0. This language of 1s and 0s is called the binary digital system. Each digit (each of the ones and zeros that make up this language) is called a bit (Binary Digit). A group of 8 bits is called a byte or octet. These 8 bits, combined in all possible ways, make 256 combinations. These 256 bytes form the ASCII (American Standard Code for Information Interchange).
Bytes are used as the unit of measure for capacity, such as for a CD, DVD, RAM, etc. We have said that 8 bits (b) are a byte (B). From here, its multiples are:
- Kilobyte (KB): 1 KB = 210 B = 1024 B
- Megabyte (MB): 1 MB = 210 KB = 220 B = 1,048,576 B
- Gigabyte (GB): 1 GB = 210 MB = 230 B = 1,073,741,824 B
- Terabyte (TB): 1 TB = 210 GB
- Petabyte (PB): 1 PB = 210 TB
Software: Definition and Types
Software is a set of computer programs, procedures, rules, documentation, and data associated with the operation of a computer system (i.e., that which cannot be physically touched). Software can be classified as follows:
- System Software: This allows the hardware to work (Windows, Linux, Unix, Mac OS, etc.).
- Programming Software: This allows programmers to develop computer programs using different programming languages in a practical way (Visual Basic, C++, Basic, Pascal, Fortran, Java, HTML).
- Application Software: This allows users to perform one or more specific tasks using a computer (word processors, office suites, games, simulation programs).
Operating Systems: An Interface
An operating system can be defined as a program or suite of software that controls the execution of other application programs and acts as an interface between the user and the computer.
Features of Operating Systems
- Convenience: An operating system makes using a computer more comfortable.
- Efficiency: An operating system allows computer system resources to be used more efficiently.
Functions from the User’s Viewpoint
- Transforms the computer into a more user-friendly work environment regarding loading and running programs, memory management, hardware verification, etc.
- Frees the user from working directly with the hardware.
Internal Functions of Operating Systems
- Distribute resources among the various processes (running programs) and among different users (if there is more than one).
- Manage computer resources (memory, CPU, I/O, etc.) appropriately in an orderly and controlled manner.
- Improve system performance.
Historical Evolution of Operating Systems
Operating systems, like hardware, have undergone changes over time, which can be grouped into generations. The evolution of hardware has driven the evolution of operating systems.
First Generation (1945-1955)
The first computers of the 1940s had no operating system. Programmers interacted directly with the hardware in machine language (0s and 1s). The first OS was created in 1956 (IBM). Basically, the only thing it did was start the execution of a program when the previous one ended. Input/Output devices were punched card readers and printers.
Second Generation (1955-1965)
Input/Output devices were perfected with tapes (faster devices that contained a list of jobs with various programs). In the 1960s, a revolution in OS concepts occurred: multitasking systems, multiuser systems, multiprocessor systems, and real-time systems appeared. At the end of the 1960s, UNIX appeared, the basis of the vast majority of existing OS today. High-level programming languages like FORTRAN also appeared.