Also known as hidden RAM, hidden memory is essentially a duplication of routines inherent in the basic input/output operating system or BIOS of a computer system. This pool of mirrored or shadow memory is then stored in a protected area of the system’s random access memory or RAM, making it easy to retrieve the copy when and as needed. Depending on the type of operating system being used, cache memory may be used at startup and at certain times during device operation. Other operating systems do not require the use of this type of memory and may even frequently use the option to disable mirrored memory as a means of allocating resources elsewhere.
man holding computer
The purpose of hidden memory is to protect the system from possible damage to the read-only memory (ROM) that is part of the overall system configuration. Older operating systems often included this specific feature as a means of copying the BIOS for easy recovery when the system was powered on, and sometimes even when specific tasks were being performed during the session. While some of the newer operating systems no longer rely on this particular approach, it is not uncommon for the default system settings to allow a copy of the BIOS to be created and stored in a secure area of RAM. The advantage of keeping this feature active is that, in the unlikely event that the BIOS housed in read-only memory is somehow corrupted,
Depending on the cache configuration, it can use a considerable amount of resources or require only a small amount to function efficiently. Users who are well versed in changing the setting can usually apply different methods relevant to specific operating systems to adjust the amount of random access memory used to store the copied data bytes. This can be especially useful if the computer system involved has a relatively low amount of memory to begin with and more memory needs to be allocated to run other programs.
While the use of flash memory may be optional on some operating systems, there is a difference of opinion as to whether the feature should be disabled or enabled. Proponents view continued use of this feature as a protective measure that may never really be necessary, but can be very important to system recovery in the unlikely event of BIOS corruption. Others point out that newer operating systems have additional protections that further reduce the chance of this type of problem, making hidden memory more or less obsolete.
