Spooler Utilities Reference Manual

Migration Considerations for Pre-D41 Spooler
Versions
Spooler Utilities Reference Manual—522295-003
H-5
New Collector Data File Capacity Requirements
Although older versions of spooler collection files are used to access jobs present at
the time of the warmstart, new jobs cannot be collected onto these files.
New Collector Data File Capacity Requirements
The number of units in a new collection file is no longer constrained by the spooler.
Instead, it is limited solely by the amount of space allocated on the disk. In addition,
unit size no longer needs to be inflated to allow use of larger collection files.
Improved Collector Performance
The elapsed time to collect jobs can be significantly shorter than in older-version
spoolers when the data file BUFFERSIZE and collector UNIT attributes are set to allow
larger buffers to be used by the collector.
You can obtain up to a 400 percent reduction in the elapsed time of collecting a job
(particularly larger jobs) if the collector can use 4K buffers to do the collection I/O.
Older-version spooler collectors, whose jobs could be no greater than 8191 units, took
advantage of this limit and retained in memory all accounting for the job’s units
allocated on disk. Because there is no longer a limit to the number of units in a job, the
new collector uses an indexing scheme that is extensible. To minimize index overhead,
the D41, D46, and D48 collector has been designed to promote contiguously allocated
units and coalesce such allocation into a single index entry. This scheme minimizes the
number of index records required for a job.
In cases where a job contains 1000 units or more and these units are largely allocated
discontiguously on the disk, overhead will be greater than in older-version spoolers. As
a result, the following operations may take a few seconds longer:

Spoolcom DEV SKIP or SKIPTO commands

PERUSE LIST specific-page command
More detailed analysis of the relative performance for these commands is available
upon request from HP.
New Collector Data File UNIT and DP2 BUFFERSIZE Settings
As in older-version spoolers, the collector UNIT attribute is the amount of disk space
allocated for a job each time space is required. The value entered is expressed in
number of blocks of 1K bytes (for example, UNIT 3 is equal to 3K bytes). Units contain
data for only one job. Unused space in a unit is unavailable for other jobs. Once a
collector data file has been initialized, the UNIT attribute cannot be altered. The
minimum UNIT value is 2 (2K bytes).
The D41 collector buffers write operations, if possible, to match the collector data file's
DP2 BUFFERSIZE attribute. This attribute is established at file creation (but can be
altered later). Valid entries for collector use are 2048 or 4096 bytes or a multiple of
2048 bytes; a setting of 512 bytes is returned with an error message. You should set