My computer knowledge

Printers  are Output devices used to prepare permanent Output devices on paper. Printers can be divided into two main categories : Impact Printers  : In this hammers or pins strike against a ribbon and paper to print the text. This mechanism is known as electro-mechanical mechanism. They are of two types. Character Printer  : It prints only one character at a time. It has relatively slower speed. Eg. Of them are Dot matrix printers.  Dot Matrix Printer  : It prints characters as combination of dots. Dot matrix printers are the most popular among serial printers. These have a matrix of pins on the print head of the printer which form the character. The Computer memory sends one character at a time to be printed by the printer. There is a carbon between the pins & the paper. The words get printed on the paper when the pin strikes the carbon. There are generally 24 pins.    Laser Printer  is a type of printer that utilizes a laser beam to produce an image on a drum. The l

     A flip flop is an electronic circuit with two stable states that can be used to store binary data. The stored data can be changed by applying varying inputs. Flip-flops and latches are fundamental building blocks of digital electronics systems used in computers, communications, and many other types of systems. Flip-flops and latches are used as data storage elements. It is the basic storage element in sequential logic. But first, let’s clarify the difference between a latch and a flip-flop. Flip flop v/s Latch The basic difference between a latch and a flip-flop is a gating or clocking mechanism. For example, let us talk about SR latch and SR flip-flops. In this circuit when you Set S as active the output Q would be high and Q’ will be low. This is irrespective of anything else. (This is an active low circuit so active here means low, but for an active high circuit active would mean high) SR Latch A flip flop, on the other hand, is synchronous and is also known as gated

                      RAM memory  (Random Access Memory) is the internal memory of the CPU for storing data, program, and program result. It is a read/write memory which stores data until the machine is working. As soon as the machine is switched off, data is erased.  Access  time in RAM is independent of the address, that is, each storage location inside the memory is as easy to reach as other locations and takes the same amount of time. Data in the RAM can be accessed randomly but it is very expensive. RAM is volatile, i.e. data stored in it is lost when we switch off the computer or if there is a power failure. Hence, a backup Uninterruptible Power System (UPS) is often used with computers. RAM is small, both in terms of its physical size and in the amount of data it can hold. RAM is of two types − Static RAM (SRAM) Dynamic RAM (DRAM) Static RAM (SRAM) The word  static  indicates that the memory retains its contents as long as power is being supplied. However,

Pin diagram of 8085 microprocessor The following image depicts the pin diagram of 8085 Microprocessor − The pins of a 8085 microprocessor can be classified into seven groups − Address bus A15-A8, it carries the most significant 8-bits of memory/IO address. Data bus AD7-AD0, it carries the least significant 8-bit address and data bus. Control and status signals These signals are used to identify the nature of operation. There are 3 control signal and 3 status signals. Three control signals are RD, WR & ALE. RD  − This signal indicates that the selected IO or memory device is to be read and is ready for accepting data available on the data bus. WR  − This signal indicates that the data on the data bus is to be written into a selected memory or IO location. ALE  − It is a positive going pulse generated when a new operation is started by the microprocessor. When the pulse goes high, it indicates address. When the pulse goes down it indicates data.

What is an Operating System? The earliest computers did not have operating systems. Every program that ran on these early systems had to include all of the code necessary to run the computer, communicate with connected hardware, and perform the computation the program was actually intended to perform. This situation meant that even simple programs were complex. As computer systems diversified and became more complex and powerful, it became increasingly impractical to write programs that functioned as both an operating system and a useful application. In response, individual mainframe computer owners began to develop system software that made it easier to write and run programs and operating systems were born. An  operating system  ( OS ) is software that manages computer hardware and system resources and provides the tools that applications need to operate. The birth of operating systems meant that programs no longer had to be written to control the entire scope of computer oper

                     CISC microprocessor CISC stands for " Complex Instruction Set Computing ." This is a type of microprocessor design. The CISC architecture contains a large set of computer instructions that range from very simple to very complex and specialized. Though the design was intended to compute complex instructions in the most efficient way, it was later found that many small, short instructions could compute complex instructions more efficiently. This led to a design called Reduced Instruction Set Computing (RISC), which is now the other major kind of microprocessor architecture. Intel Pentium processors are mainly CISC-based, with some RISC facilities built into them, whereas the PowerPC processors are completely RISC-based.

    Intel 8085 microprocessor            Block diagram of Intel 8085 microprocessor                        8085 is pronounced as "eighty-eighty-five" microprocessor. It is an 8-bit microprocessor designed by Intel in 1977 using NMOS technology. It has the following configuration −                   8-bit data bus A 16-bit program counter A 16-bit stack pointer Six 8-bit registers arranged in pairs: BC, DE, HL Requires +5V supply to operate at 3.2 MHZ single phase clock It is used in washing machines, microwave ovens, mobile phones, etc. 8085 Microprocessor – Functional Units 8085 consists of the following functional units − Accumulator It is an 8-bit register used to perform arithmetic, logical, I/O & LOAD/STORE operations. It is connected to internal data bus & ALU. Arithmetic and logic unit As the name suggests, it performs arithmetic and logical operations like Addition, Subtraction, AND, OR, etc. on 8-bit data. General purpos