NON-VSAM ATTRIBUTES

Block Size:- Describes the maximum length in bytes of a data block.

⮚ Must be a multiple of the record  size and no more than 32760 bytes

⮚ Block size is inversely proportional to I/O’s.

⮚ When we give more Block size I/o count will be less . If block size is less, then I/o will be used much.

⮚ Block size should not exceed 2 Gb.

Record Length:- Describes the logical record length in bytes.

LRECL – record length size – 80, 80 characters in a row.

Record Format:- Describes the way records are organized.

F (Fixed):- Fixed means that one physical block on disk is one logical record and all the blocks and records are the same size. 

• If the record length is 80 then blocks will also be 80.

FB (Fixed Blocked):- This format designation means that several logical records are combined into one physical block. 

• Dataset will be in blocks and fixed. 

for eg:- record length is 80 then blocks also will be multiples of 80. 

i.e if you write a data in a line for 45 lines and give 80 remaining space will be wasted.

F (Fixed):- Fixed means that one physical block on disk is one logical record and all the blocks and records are the same size. 

• If the record length is 80 then blocks will also be 80.

FB (Fixed Blocked):- This format designation means that several logical records are combined into one physical block. 

• Dataset will be in blocks and fixed. 

for eg:- record length is 80 then blocks also will be multiples of 80. 

i.e if you write a data in a line for 45 lines and give 80 remaining space will be wasted.

U (Undefined):- This format consists of variable-length physical records and blocks with no predefined structure. It is normally used only for executable modules.

• U is used for load libraries and object modules.

Space Parameters:- This parameter specifies the space units that will be used to allocate a non-VSAM dataset.

Space units:- BLKS, TRKS, CYLS, KB, MB, BYTES or RECORDS(for the last AVGREC is needed).

Primary  quantity:- Specifies the initial allocation amount.

Secondary quantity:- Specifies an additional allocation amount. The system does not allocate additional space until it is needed.

Directory blocks:- You must code for a partitioned data set, to indicate the number of blocks the system must reserve for the directory.

• Directory  blocks , Here is where we give the value for 6(n)-1

Average record unit:- Used when allocating in records or blocks (U-bytes, K-kilobytes, M-megabytes)

• U—Use a scale of 1
• K—Use a scale of 1024 
• M—Use a scale of 1048576

Dataset Organization:- LIBRARY, PDS, LARGE, BASIC