The process of moving vehicles into an automotive repair shop – working on them – then returning them to the parking lot is very similar to the way a computer works. A computer processor moves information from disk into memory – modifies it – then writes it back to disk. A computer without enough memory is similar to a shop without enough bays. A computer processor that is not fast enough to keep up with its workload is similar to auto repair shop employees having to move vehicles in and out of the shop more than they can keep up with. And a shop without enough parking outside is similar to a computer without enough disk space. Following are correlations between vehicle movement in an auto repair shop and computer processing:
- Computer Memory Versus Shop Bays – The memory (RAM) on a computer is similar to the bays within an auto repair shop. On a computer information is moved into memory – modified – then returned to disk. In an auto repair shop – vehicles are moved into the shop – worked on then returned to the parking lot. Like a shop that doesn’t have enough bays causing more vehicle movement a computer that doesn’t have enough memory will result in information being moved in and out more than desired thus negatively impacting performance. In computer jargon this circumstance is referred to as the computer being ‘Memory Bound’.
- Computer Processor Versus Shop Employees – The processor (CPU) on a computer performs a function similar to the employees in an auto repair shop. In an auto repair shop employees move vehicles into the shop – work on them – then move them back to the parking lot. A computer processor moves information from the disk into memory – modifies it – then writes it back to disk. If the employees in the auto repair shop can’t keep up with the vehicle activity – productivity will suffer. Likewise if a computer processor doesn’t have the speed to keep up with moving data into memory – updating it – then writing it back to disk – performance will suffer. Information being moved into and out of memory is referred to as ‘Paging’. When a processor has to move memory into and out of memory more often than it should the system is said to be ‘Thrashing’. When a computer has a processor that’s overloaded it’s said to be ‘Processor Bound’.
- Hard Drive versus Shop Parking Lot – In an auto repair shop when a vehicle is not being worked on it is moved to the parking area outside the shop. Likewise when information is done being modified by a computer it is written to the hard disk. Just as when there is not adequate parking space outside the shop and people have to spend extra time moving vehicles – when a computer doesn’t have enough disk space available it has to work harder writing information to disk.