Cylinder 1024
Encyclopedia
Cylinder 1024 is the first cylinder
of a hard disk
that was inaccessible in the original IBM PC compatible
hardware specification, interrupt 13h, which uses cylinder-head-sector
addressing. At boot time very old BIOS
of many PCs could only access the first 1024 cylinders, numbered 0 to 1023 as CHS addressing only defines 10 bits for the cylinder count (2^10=1024).
This was a problem for operating system
s on the x86 platform as the BIOS must be able to load the bootloader and the entire kernel image into memory. Both of these must, therefore, be located on the first 1024 cylinders of the disk.
Older versions of Microsoft Windows
resolved this by necessitating that the operating system was installed to the first partition. Because of this bug, users of the Linux
operating system have traditionally created a /boot partition to reside within the first 1024 cylinders of the disk, containing little more than the kernel and bootloader.
Cylinder (disk drive)
A disk drive cylinder is a division of data in a disk drive, as used in the CHS addressing mode of a Fixed Block Architecture disk or the cylinder–head–record addressing mode of a CKD disk. The concept is concentric, hollow, cylindrical slices through the physical disks , collecting the respective...
of a hard disk
Hard disk
A hard disk drive is a non-volatile, random access digital magnetic data storage device. It features rotating rigid platters on a motor-driven spindle within a protective enclosure. Data is magnetically read from and written to the platter by read/write heads that float on a film of air above the...
that was inaccessible in the original IBM PC compatible
IBM PC compatible
IBM PC compatible computers are those generally similar to the original IBM PC, XT, and AT. Such computers used to be referred to as PC clones, or IBM clones since they almost exactly duplicated all the significant features of the PC architecture, facilitated by various manufacturers' ability to...
hardware specification, interrupt 13h, which uses cylinder-head-sector
Cylinder-head-sector
Cylinder-head-sector, also known as CHS, was an early method for giving addresses to each physical block of data on a hard disk drive. In the case of floppy drives, for which the same exact diskette medium can be truly low-level formatted to different capacities, this is still true.Though CHS...
addressing. At boot time very old BIOS
BIOS
In IBM PC compatible computers, the basic input/output system , also known as the System BIOS or ROM BIOS , is a de facto standard defining a firmware interface....
of many PCs could only access the first 1024 cylinders, numbered 0 to 1023 as CHS addressing only defines 10 bits for the cylinder count (2^10=1024).
This was a problem for operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...
s on the x86 platform as the BIOS must be able to load the bootloader and the entire kernel image into memory. Both of these must, therefore, be located on the first 1024 cylinders of the disk.
Older versions of Microsoft Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
resolved this by necessitating that the operating system was installed to the first partition. Because of this bug, users of the Linux
Linux
Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...
operating system have traditionally created a /boot partition to reside within the first 1024 cylinders of the disk, containing little more than the kernel and bootloader.