US 5,969,893 A · Tape pre-formatting with uniform data storage segments selectively mapped to fixed or variable sized independently addressable data storage partitions

Abstract

Various data storage formats help to efficiently locate, read, and write user data stored on magnetic tape media. A tape is formatted by writing multiple segment-headers, free from any interleaved access of user data Adjacent segment-headers are spaced by a predetermined interval to define multiple data storage segments. Segment-headers all contain a unique key, which is copied into a key index to identify valid segments. After formatting, normal tape accesses can be performed. Without erasing any old headers or data, a new formatting scheme can be established by writing new segment-headers on the tape. The new segment-headers include a new unique key, replacing the previous key in the key index. Previous segment-headers stored on the tape are ignored, since they lack the updated key. Segments may be selectively grouped to provide independently addressable partitions. Mapping between segments and partitions can use a fixed relationship (e.g. one-to-one), or each partition may be variably sized according to the amount of data to be stored therein. Variable-sized partitions may be automatically padded with a selected number of empty segments. Another feature is flexible-capacity scaling, which distributes an ordered set of device blocks on a multi-track magnetic tape medium. The device blocks are bi-directionally stored in a continuous configuration of multiple adjacent stacked serpentine patterns occupying some or all of the tape. This configuration permits sequential access of all device blocks without advancing the tape medium to skip over regions between adjacent device blocks.

Claims25

Dependent claims

A method for pre-formatting magnetic tape media, comprising the steps of:

defining a first plurality of data storage segments on a magnetic tape medium by writing a first plurality of segment-headers to the tape medium, said writing being performed free from any interleaved writing of user data to the tape medium, adjacent ones of said first plurality of segment-headers being evenly spaced apart by a first predetermined interval, each one of said first plurality of segment-headers containing a first predetermined key common to all of said first plurality of segment-headers;
and
storing the first predetermined key in a key index to identify the first plurality of segments as being most recent.

A method for formatting magnetic tape media, comprising the steps of:

defining a first plurality of data storage segments on a magnetic tape medium by writing a first plurality of segment-headers to the tape medium, said writing being performed free from any interleaved writing of user data to the tape medium, adjacent ones of said first plurality of segment-headers being evenly spaced apart by a first predetermined interval, each one of said first plurality of segment-headers containing a first predetermined key common to all of said first plurality of segment-headers;
wherein the segments are sequentially ordered according to a predetermined scheme;
storing the first predetermined key in a key index to identify the first plurality of segments as being most recent;
receiving a first set of device blocks to be written;
sequentially writing the first set of device blocks to a minimum number of at least one segment needed to contain the first set of device blocks;
and
establishing as a first partition said at least one segment, and establishing as a second data partition all subsequently ordered segments.

4 more elements

Dependencies are inferred from the claim text.

Tape pre-formatting with uniform data storage segments selectively mapped to fixed or variable sized independently addressable data storage partitions

Life of this patent

Tape pre-formatting with uniform data storage segments selectively mapped to fixed or variable sized independently addressable data storage partitions

Life of this patent

Abstract

Claims25