Linear Data Set

From HandWiki

A linear data set (LDS) is a type of data set organization used by IBM's VSAM computer data storage system.[1]:5

The LDS has a control interval size of 4096 bytes to 32768 bytes[2] in increments of 4096.[1]:31 A LDS does not have embedded control information, because it does not contain control information, the LDS cannot be accessed as if it contained individual records.[3]

Addressing within an LDS is by Relative Byte Address (RBA), which allows it to be used by systems such as IBM Db2 or the Operating system.[clarification needed] The benefit of this is that systems such as the OS can access multiple disk spindles and view it as a single storage implementation. The limitations of this, though, is that this does not make this particularly useful to higher level abstraction levels.[original research?] Data In Virtual[4] (DIV) and Window services[5] provide an alternative method to direct use of VSAM to access an LDS with a CI size of 4096.

See also

References

ASMGUIDE
z/OS 2.5 MVS Programming: Assembler Services Guide. IBM. September 30, 2021. SA23-1368-50. https://www.ibm.com/servers/resourcelink/svc00100.nsf/pages/zOSV2R5sa231368/$file/ieaa600_v2r5.pdf. 
Other citations
  1. 1.0 1.1 Lovelace, Mary; Dovidauskas, Jose; Salla, Alvaro; Sokal, Valeria (March 2013). "Chapter 1. VSAM basics". VSAM Demystified. Redbooks (3 ed.). IBM. http://www.redbooks.ibm.com/pubs/pdfs/redbooks/sg246105.pdf. 
  2. z/OS 2.5 DFSMS Using Data Sets. IBM. September 30, 2021. p. 91. SC23-6855-50. https://www-01.ibm.com/servers/resourcelink/svc00100.nsf/pages/zOSV2R5sc236855/$file/idad400_v2r5.pdf. 
  3. "IBM Knowledge Center" (in en-US). 27 March 2014. https://www.ibm.com/support/knowledgecenter/en/SSLTBW_2.1.0/com.ibm.zos.v2r1.idad400/d4261.htm. 
  4. ASMGUIDE, pp. 225-248, Chapter 14. Data-in-virtual.
  5. ASMGUIDE, pp. 293-310, Chapter 17. Window Services.