A storage block is a physical sector

Disk sector

In computer disk storage, a sector is a subdivision of a track on a magnetic disk or optical disc. Each sector stores a fixed amount of user data. Traditional formatting of these storage media provides space for 512 bytes or 2048 bytes of user-accessible data per sector...

 on the surface of a disk or diskette. It is the smallest unit of transference between the main memory and a given disk drive.

In the IBM mainframe

IBM mainframe

IBM mainframes are large computer systems produced by IBM from 1952 to the present. During the 1960s and 1970s, the term mainframe computer was almost synonymous with IBM products due to their marketshare...

 terminology, a block is the minimal physical division of data in a disk drive, either as used on a Fixed Block Architecture

Fixed Block Architecture

Fixed Block Architecture is a disk layout in which each addressable record on disk is of the same size. The term fell out of use, since nearly all modern disk drives use this principle, termed logical block addressing and usually having a constant addressable block size of 512 bytes.- Count Key...

 (FBA) disk or in the Cylinder-Head-Record (CCHHRR) addressing mode of a Count-Key-Data (CKD) disk. Blocks are separated on the track

Track (disk drive)

A disk drive track is a circular path on the surface of a disk or diskette on which information is magnetically recorded and from which recorded information is read....

 by "inter-record gaps" (approx. 6 bytes on IBM 3380 and IBM 3390 disk drive models). The number of blocks per tracks depends on the block size and the specific gap size associated to each block. Each block can contain a discrete quantity of logical record

Record (computer science)

In computer science, a record is an instance of a product of primitive data types called a tuple. In C it is the compound data in a struct. Records are among the simplest data structures. A record is a value that contains other values, typically in fixed number and sequence and typically indexed...

s or it can be empty. Logical records are defined by the database

Database

A database is an organized collection of data for one or more purposes, usually in digital form. The data are typically organized to model relevant aspects of reality , in a way that supports processes requiring this information...

 designer or application designer; see Data set (IBM mainframe)

Data set (IBM mainframe)

data set , dataset , is a computer file having a record organization. The term pertains to the IBM mainframe operating system line, starting with OS/360, and is still used by its successors, including the current z/OS. Those systems historically preferred this term over a file...

.

See also

• Track (disk drive)
  Track (disk drive)
  A disk drive track is a circular path on the surface of a disk or diskette on which information is magnetically recorded and from which recorded information is read....
  
  
• Block (data storage)
  Block (data storage)
  In computing , a block is a sequence of bytes or bits, having a nominal length . Data thus structured are said to be blocked. The process of putting data into blocks is called blocking. Blocking is used to facilitate the handling of the data-stream by the computer program receiving the data...
  
  
• Record (computer science)
  Record (computer science)
  In computer science, a record is an instance of a product of primitive data types called a tuple. In C it is the compound data in a struct. Records are among the simplest data structures. A record is a value that contains other values, typically in fixed number and sequence and typically indexed...
  
  
• Data set (IBM mainframe)
  Data set (IBM mainframe)
  data set , dataset , is a computer file having a record organization. The term pertains to the IBM mainframe operating system line, starting with OS/360, and is still used by its successors, including the current z/OS. Those systems historically preferred this term over a file...