BIOS: Difference between revisions

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The term '''Basic Input Output System (BIOS)''' dates back to the original IBM personal computer of the early 1980's. The BIOS was an [[API]], located in non-volatile memory, and thus was said to be ''firmware''.  The BIOS chip in a personal computer originally provided an information-hiding layer between the (then) Disk Operating System (DOS) and the hardware. The contents of an IBM personal computer's firmware include the following essential parts:
{{subpages}}
The '''Basic Input Output System''' ('''BIOS''') is  a series of instructions (software code) which is a part of many modern [[computer]]s, responsible for basic functions such as controlling the [[keyboard]] or booting up an [[operating system]]. The term dates back to the original [[IBM]] personal computer of the early 1980's.
 
This firmware typically was written to a [[CMOS]] (complimentary metal oxide semiconductor) chip, and some computer enthusiasts used the terms "BIOS" and "CMOS" interchangeably.
 
==Breaking down the BIOS==
The BIOS was an [[API]] that served as a [[layer of abstraction]], located in non-volatile memory known as CMOS, and thus is said to be ''[[firmware]]''.  The BIOS [[chip]] in a personal computer originally provided an information-hiding layer between the (then) Disk Operating System ([[DOS]]) and the hardware.
 
The contents of an IBM personal computer's firmware include the following essential parts:


* power-on self test (POST) routines
* power-on self test (POST) routines
Line 7: Line 15:
* the boot-strap loader program, which looks at the first sector of the boot drive (the so-called ''Master Boot Record'', or MBR) to locate an operating system, loads the OS into memory, and then transfers control to the OS kernel
* the boot-strap loader program, which looks at the first sector of the boot drive (the so-called ''Master Boot Record'', or MBR) to locate an operating system, loads the OS into memory, and then transfers control to the OS kernel


The BIOS's role as an information-hiding layer was very important.  It allowed many different hardware vendors to create components such as motherboards and add-in cards for the computer, without the operating system code needing to be changed.  Because the BIOS was in firmware, it also meant that consumers could upgrade their own disk drives.  The latter is an important point, because in 2008, 25 years after the IBM personal computer's BIOS became the ''de facto'' standard to booting Wintel computers, an industry consortium is moving to surplant BIOS and MBR booting (admittedly limited in capability) with a newer standard called [[EFI]].
The BIOS's role as an information-hiding layer was very important.  It allowed many different hardware vendors to create components such as [[motherboard]]s and add-in cards for the computer, without the operating system code needing to be changed.  Because the BIOS was in firmware, it also meant that consumers could upgrade their own [[disk drive]]s.  The latter is an important point, because in 2008, 25 years after the IBM personal computer's BIOS became the ''de facto'' standard to booting Wintel computers, an industry consortium is moving to supplant BIOS and MBR booting (admittedly limited in capability) with a newer standard called [[EFI]].
 
==The BIOS has been deprecated==
There are many catalogs of the limitations of the long-standing BIOS system in Wintel computers.  The proposed standard to replace BIOS, called Extensible Firmware Interface (EFI), was originated by Intel around 2000 and has been converted into an industry consortium (UEFI).  It is used in 2008 by the wildly popular [[Apple_Inc.|Apple]] [[Macbook]] and [[Macbook Pro]] notebook computers.
 
There are many available online resources describing the benefits of UEFI, but very few that discuss the downside of the proposed emerging standard for consumers, which is, that the boot software is no longer firmware but is, instead, at least partly on the boot drive itself in a special, pre-created [[disk partition]].  Consumers currently lack the appropriate utilities and software tools to deal well with EFI, though this may be expected to change over time.


There are many catalogs of the limitations of the long-standing BIOS system in Wintel computers.  The proposed standard to replace BIOS, called Extensible Firmware Interface (EFI), was originated by Intel around 2000 and has been converted into an industry consortium (UEFI).  It is used in 2008 by the wildly popular Apple Macbook laptop computer.  There are many available online resources describing the benefits of UEFI, but very few that discuss the downside of the proposed emerging standard for consumers, which is, that the boot software is no longer firmware but is, instead, at least partly on the boot drive itself in a special, pre-created partition.  This means that consumers will no longer find it easy, or even possible, to replace a boot drive with a larger boot drive bought from a third-party manufacturer.  Consumers, at least for now, will be limited to obtaining a larger or replacement boot drive from a computer's manufacturer, ''if'' the manufacturer is willing to sell them one, and at any cost which that vendor decides to charge.  This loss of flexibility to consumers has not yet been widely recognized by consumers or acknowledged by the industry.  Some drive manufacturers (those chosen by computer integrators) will likely benefit wildly, in that consumers will likely have to pay higher prices for replacement drives, whereas third party manufacturers will possibly lose market share.  In the long run, there is the possibility of harm to the thriving, competitive and open market for computer disk drives which has driven prices to their current low.  This conundrum is an example of how the computer hardware market has developed a complex ecology comparable, in many ways, to ecological problems in nature.  So while EFI follows all the time-honored principles of open-source and open development in its consortium nature, it may have the opposite effect on consumers and third party manufacturers, ironically that of locking in certain few vendors to the detriment of many others, and costing consumers more as a result.
==Footnotes==
{{reflist|2}}

Latest revision as of 14:23, 15 July 2008

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The Basic Input Output System (BIOS) is a series of instructions (software code) which is a part of many modern computers, responsible for basic functions such as controlling the keyboard or booting up an operating system. The term dates back to the original IBM personal computer of the early 1980's.

This firmware typically was written to a CMOS (complimentary metal oxide semiconductor) chip, and some computer enthusiasts used the terms "BIOS" and "CMOS" interchangeably.

Breaking down the BIOS

The BIOS was an API that served as a layer of abstraction, located in non-volatile memory known as CMOS, and thus is said to be firmware. The BIOS chip in a personal computer originally provided an information-hiding layer between the (then) Disk Operating System (DOS) and the hardware.

The contents of an IBM personal computer's firmware include the following essential parts:

  • power-on self test (POST) routines
  • a tiny database about the hardware configuration
  • a setup program for modifying the database (this program could only be run by pressing a certain key, or group of keys, during the boot process; exactly which keys varied per computer manufacturer)
  • a set of routines for accessing standard hardware components such as disk drives and serial ports
  • the boot-strap loader program, which looks at the first sector of the boot drive (the so-called Master Boot Record, or MBR) to locate an operating system, loads the OS into memory, and then transfers control to the OS kernel

The BIOS's role as an information-hiding layer was very important. It allowed many different hardware vendors to create components such as motherboards and add-in cards for the computer, without the operating system code needing to be changed. Because the BIOS was in firmware, it also meant that consumers could upgrade their own disk drives. The latter is an important point, because in 2008, 25 years after the IBM personal computer's BIOS became the de facto standard to booting Wintel computers, an industry consortium is moving to supplant BIOS and MBR booting (admittedly limited in capability) with a newer standard called EFI.

The BIOS has been deprecated

There are many catalogs of the limitations of the long-standing BIOS system in Wintel computers. The proposed standard to replace BIOS, called Extensible Firmware Interface (EFI), was originated by Intel around 2000 and has been converted into an industry consortium (UEFI). It is used in 2008 by the wildly popular Apple Macbook and Macbook Pro notebook computers.

There are many available online resources describing the benefits of UEFI, but very few that discuss the downside of the proposed emerging standard for consumers, which is, that the boot software is no longer firmware but is, instead, at least partly on the boot drive itself in a special, pre-created disk partition. Consumers currently lack the appropriate utilities and software tools to deal well with EFI, though this may be expected to change over time.

Footnotes

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