Characteristics of Large Format Data Sets

The following characteristics describe large format data sets:

Large format data sets have a maximum of 16 extents on each volume.
A large format data set can occupy up to 16␠777␠215 tracks on a single volume.
Each large format data set can have a maximum of 59 volumes. Therefore, a large format data set can have a maximum of 944 extents (16 times 59).
A large format data set can occupy any number of tracks, without the limit of 65␠535 tracks per volume.
The minimum size limit for a large format data set is the same as for other sequential data sets that contain data: one track, which is about 56␠000 bytes.
Primary or secondary space can both exceed 65␠535 tracks per volume.
Large format data sets can be on SMS-managed DASD or non-SMS-managed DASD.
Large format data sets can be cataloged or not cataloged.
Programs using BSAM with the NOTE or POINT macros may require adjustments to use large format data sets, and they must specify the BLOCKTOKENSIZE=LARGE parameter on the DCBE macro unless the data set contains less than 65␠536 tracks on the current volume and is being opened with the INPUT or UPDAT option.
Programs using EXCP may require adjustments to use large format data sets, and they must specify the BLOCKTOKENSIZE=LARGE parameter on the DCBE macro unless the data set contains less than 65␠536 tracks on the current volume and is being opened with the INPUT option.
For other considerations when opening a large format data set, see Opening and Closing Large Format Data Sets.