most cases, the processing speed far exceeds the ability of input devices to supply information. One common limitation of most input devices is that each involves some mechanical operation. For example, the movement of a tape drive or card feeder. Because a mechanical movement of some part of these devices cannot take place fast enough to match electronic speeds with the computer, these input devices limit the speed of operation of the associated computer. This is particularly evident in cases where successive operations are dependent upon the receipt of new data from the input medium. Several methods of speeding up mechanical operation have been devised, all of which are designed to move a smaller mass a shorter distance and with greater driving force. Many of these designs have been directed toward increasing the drive speed of magnetic tapes. For example, present-day tape drives can pass up to 400 inches of tape per second of a tape reading head. Card readers can read up to 2,000 cards per minute. Present-day disk systems operate at speeds up to 3,600 RPM. The comparative rates of data for these systems are as follows: . Card systems—2,700 characters per second . Tape systems—350,000 characters per second . Disk systems—15,000,000 characters per second Another method of entering data into a computer, which we have not previously mentioned, is to link two or more computers together and program them to communicate with each other. This is perhaps the fastest method of entering or extracting data from a computer. An example of this method is the data link. Output Devices Output information is also made available in three forms: . Displayed information, such as codes or symbols presented on a monitor screen, that is used by the operator to answer questions or make decisions. . Control signals, which is information that operates a control device, such as a lever, aileron, or actuator. . Recordings, which is information stored in a machine language or human language on tapes or printed media. Devices that store or read output information include magnetic tapes, punched cards, punched paper tapes, monitors, electric typewriters, and high-speed printers. INTEGRATED CIRCUIT (IC) TECHNOLOGY Learning Objective: Identify integrated circuit classifications and various types of integrated circuits. Modern digital computers are made with ICs. ICs provide the most economical and practical method of implementing the circuits required to carry out the functions of a digital computer. IC CLASSIFICATIONS ICs fall into four basic levels of complexity. These are small scale integration (SSI), medium scale integration (MSI), large scale integration (LSI), and very large scale integration (VLSI). The designations define the size and complexity of individual ICs. Small Scale Integration (SSI) SSI circuits contain very little circuitry, generally fewer than 10 circuits no more complex than a typical logic gate. Typical SSI circuits include multiple logic gates, flip-flops, and simple combinational logic circuits. Medium Scale Integration (MSI) MSI circuits are more complex and sophisticated than SSI circuits. Most MSI circuits contain 12 or more circuits equivalent in complexity to a typical logic gate.    MSI circuits are functional in nature in that the y perform a specific logic operation with no further interconnection. Typical MSI circuits include counters, shift registers, arithmetic-logic circuits, decoders, multiplexer, and other combinational and sequential logic circuits. MSI circuits are highly beneficial because they significantly cut design time. They also reduce the number of ICs in design, minimize circuit wiring, and reduce size and power consumption. Most digital equipment can be 8-12