High Memory Area (HMA)

HMA is the first 65,520 bytes (64KB less 16 bytes) of extended memory. It is speciall because it is an only part of extended memory that can be used by the PC while operating in real mode.

MS-DOS loads portion of its code in it , so other application can use area below 640KB.

A software driver called an A20 handler must be run to allow the processor to access the HMA.

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Tweezers

This tool is used tp piking up very small objects like small screws that are inconvenient to pick with human hand.

Asyncronous Communication

Asynchronous &is any data transmission that does not link the two devices with a common data clock. A Signal called a start bit is sent at the beginning of each segment, & a signal called a stop bit is sent at the end, these let the receiving device note the baundries(beginning & end) of a transmission packet. Early PC modems were almost Asynchronous devices operating at speeds of no more than 18,000 bps.

Diference between laptop & desktop computer

Most laptop processors are soldered directly in the motherboard, which means they cannot be removed. If there is some error in laptop processor, the entire motherboard needs to be replaced. Laptops processors can be slowed down when they are not running to their full capacity. The processor uses a technique called processor trotling that allows the operating system to put the processor in active sleep mode or shutdown mode. Laptop processors run at reduced clock rate than desktop processors. This helps them to produce less heat when running at full capacity. Laptop processors consume less power which though make them a slow performer but it greatly helps them to save battery life.

WorkStation Care

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