Record Management Services (RMS)

The maximum size of a RMS file has no built in limitation other than the 32 bit virtual block number (VBN). In terms of blocks, a single file is limited to a VBN that must be described in 32 bits. So the maximum size of a RMS file is about 4.2 billion (2³² – 1 = 4,294,967,295) blocks. In terms of bytes, this is equivalent to 2 terabytes.

 The logical ordering of ODS (On-Disk Structure) structures is listed below in order of ascending hierarchy:

• Blocks

• Clusters

• Extents

• Files

• Volumes

• Volume Sets

Calculating Version Number

version number = [(generation number – 1) * 100] + generation version-number +1

 Version number larger than 32,767 are divided by 32,768; the integer remainder becomes the version number. On output, the generation number is derived from the version number with this calculation:

 generation number = [(version number – 1)/100] + 1

 If there is a remainder after the version number is divided by 100, the remainder becomes the generation version number. It is not added to 1 to form the generation number.

 

Creation Date and Expiration Date Fields

The creation date field contains the date the file is created. The expiration date field contains the date the file expires. The system interprets the expiration date of the first file on a volume as the date that both the file and the volume expire. The creation and the expiration dates are stored in Julian format. To write dates other than the defaults in the date fields in this label, we need to specify the creation date filed (CDT) and the expiration date field (EDT) of the RMS date and time extended attribute block (XABDAT).

 When one does not specify a creation date, RMS defaults the current date to the creation date field. To specify a zero creation date, one must specify a year before 1900. If one specifies a binary zero in the date field, the system will write the current date to the field.