Computing revision

Computing revision

1. Storage

   • Computer data storage, often called storage or memory, is a technology consisting of computer components and recording media that are used to retain digital data.

2. CPU

   • A central processing unit (CPU), also called a central processor or main processor, is the electronic circuitry within a computer that carries out the instructions of a computer program by performing the basic arithmetic, logic, controlling, and input/output (I/O) operations specified by the instructions. The computer industry has used the term "central processing unit" at least since the early 1960s. Traditionally, the term "CPU" refers to a processor, more specifically to its processing unit and control unit (CU), distinguishing these core elements of a computer from external components such as main memory and I/O circuitry.

3. RAM/ROM

   • A Random-Access Memory device allows data items to be read or written in almost the same amount of time irrespective of the physical location of data inside the memory. In contrast, with other direct-access data storage media such as hard disks, CD-RWs, DVD-RWs and the older magnetic tapes and drum memory, the time required to read and write data items varies significantly depending on their physical locations on the recording medium, due to mechanical limitations such as media rotation speeds and arm movement.
   • Read-only memory (ROM) is a type of non-volatile memory used in computers and other electronic devices.

4. Binary-denary and denary-binary

   • To calculate the value of a number in either denary or binary, you can multiply each digit by the appropriate multiplier and add them together to get the total. In denary, each digit from right to left is multiplied by 10 to the corresponding power, starting with 0.
   • Learn how to convert a denary number into a binary number using the divide by two method, with a worked example. If you keep dividing a denary number by two and noting down the remainders until you have nothing left, you'll end up with a line of ones and zeroes. Flipping that number will give you the binary number.

5. ASCII

   • ASCII stands for American Standard Code for Information Interchange. Below is the ASCII character table, including descriptions of the first 32 characters. ASCII was originally designed for use with teletypes, and so the descriptions are somewhat obscure and their use is frequently not as intended.

6. Algorithm

   • an algorithm is a set of instructions, typically to solve a class of problems or perform a computation. Algorithms are unambiguous specifications for performing calculation, data processing, automated reasoning, and other tasks.