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Hard disk and other storage drives are subject to failures (see hard disk drive failure) which can be classified into two basic classes: Predictable failures which result from slow processes such as mechanical wear and gradual degradation of storage surfaces. Monitoring can determine when such failures are becoming more likely.
Device configuration overlay (DCO) is a hidden area on many of today's hard disk drives (HDDs). Usually when information is stored in either the DCO or host protected area (HPA), it is not accessible by the BIOS (or UEFI), OS, or the user.
A hard disk drive failure occurs when a hard disk drive malfunctions and the stored information cannot be accessed with a properly configured computer. A hard disk failure may occur in the course of normal operation, or due to an external factor such as exposure to fire or water or high magnetic fields , or suffering a sharp impact or ...
In the normal operation of a hard drive, the detection and remapping of bad sectors should take place in a manner transparent to the rest of the system and in advance before data is lost. There are two types of remapping by disk hardware: P-LIST (mapping during factory production tests) and G-LIST (mapping during consumer usage by disk microcode).
In computer storage, fragmentation is a phenomenon in which storage space, such as computer memory or a hard drive, is used inefficiently, reducing capacity or performance and often both. The exact consequences of fragmentation depend on the specific system of storage allocation in use and the particular form of fragmentation.
On SCSI hard disk drives, the SCSI controller can directly control spin up and spin down of the drives. Some Parallel ATA (PATA) and Serial ATA (SATA) hard disk drives support power-up in standby (PUIS): each drive does not spin up until the controller or system BIOS issues a specific command to do so. This allows the system to be set up to ...
A related concept is the "space leak", which is when a program consumes excessive memory but does eventually release it. [ 3 ] Because they can exhaust available system memory as an application runs, memory leaks are often the cause of or a contributing factor to software aging .
For example, the first commercial hard drive, IBM's RAMAC in 1957, supplied 3.75 MB for $34,500, or $9,200 per megabyte. In 1989, a 40 MB hard drive cost $1200, or $30/MB. And in 2018, 4 Tb drives sold for $75, or 1.9¢/GB, an improvement of 1.5 million since 1989 and 520 million since the RAMAC.