HP e3000 MPE/iX System Software Maintenance Manual (Release C.75.00) > Chapter 3 Planning for Your Task

3.6 Estimating Disk Space

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Read the subsections in this section:

Non-Contiguous Disk Space Requirements
Contiguous Disk Space Requirements
Disk Space Error Messages

Before you begin to modify your system software make sure that you have enough disk space to update your system. Modifying system software includes: updating the version, reinstalling your system software, adding on purchased products from the SUBSYS tape, or applying patches. There are three types of disk space requirements that are referenced during the modification process:

Permanent (net) amount of non-contiguous disk space
required for the system software after it is modified.
Maximum (peak) amount of non-contiguous disk space
required during the system software modification process.
Amount of contiguous disk space
that the UPDATE tool requires to modify the system software.

NOTE: The disk space values listed in this section are maximum estimated values only. The actual amount of disk space used on your system will vary.

Non-Contiguous Disk Space Requirements

Table 3-5 Non-Contiguous Disk Space Sectors "Non-Contiguous Disk Space Sectors," lists the amount of non-contiguous disk space sectors required for the three operating system components (SLT, FOS, SUBSYS) and PowerPatch of the currently supported versions of the operating system software.

During the modification process, some files are duplicated temporarily, and sometimes older versions of files are retained temporarily. This causes the "in process" (or peak) amount of disk space usage to be greater than the "final" (or net) amount of disk space usage when the modification is complete.

You must have the peak amount of disk space available on your system during the process to successfully modify your system.

The combined System Load Tape (SLT) and Fundamental Operating System (FOS) are the minimum requirements for any system software version. Ensure that you have enough room on LDEV 1 for all the SLT files. The FOS files do not have to go onto LDEV 1.

Table 3-5 Non-Contiguous Disk Space Sectors

System Software Components	Version
	C60.00		C65.00		C70.00		C75.00
	Peak	Net	Peak	Net	Peak	Net	Peak	Net
SLT only^[1]	n/a	1274000	n/a	1287000	n/a	1273000		1504000
SLT and FOS	2821000	2533000	2987000	2660000	3197000	2846000	3990000	3642000
SLT, FOS, Full SUBSYS	3926000	3489000	4111000	3689000	4054000	3604000	4822784	4822784
^[1] Provided for reference only. An operational system requires the SLT and FOS files at a minimum.

IMPORTANT: Values for Express and PowerPatch 7.0 versions are given in the Read Before Installing for each release after C.70.00.

There are several conditions under which you need additional non-contiguous disk space. Refer to the appropriate following subsection for information on estimating non-contiguous disk space for your specific task.

Updating your system software.
Adding-on new SUBSYS products to your system software.
Applying PowerPatch to your system software.
Applying Reactive patches to your system software.
Distributing Staging Area to a remote system.

Disk Space Estimate for Updating

To estimate the amount of additional permanent (net) non-contiguous disk space required to update your system software, subtract the value for your current version from the value for the version you are updating to.

Record the disk space sectors required for the Update on your checklist.

Disk Space Estimate for Add-on

The values are listed in Table 3-1 System Software Media Requirements "Non-Contiguous Disk Space Requirements," for the SUBSYS (purchasable subsystem products) are the maximum for all possible purchasable products.

Estimate purchased product (SUBSYS) disk space based on the number and kind of software subsystem products that you purchased.

If you are not adding-on any new purchased products, the disk space sectors currently being used by your existing products will remain the same.

Record the estimated disk space required for SUBSYS products on your checklist.

Disk Space Estimate for PowerPatch or Express

The disk space required is listed in the section, "Disk Space Requirements," in the Read Before Installing that comes with the PowerPatch or Express media.

Record the disk space required for the PowerPatch or Express on your checklist.

Disk Space Estimate for Reactive Patch

Reactive patches vary extensively in the amount of disk space they require. Reactive patches usually replace existing files, and the increase in disk space is very little. If you want to make a worst case estimate for disk space, use the amount of disk space used by the reactive patch and add that to the disk space requirement for LDEV 1.

Record the estimated disk space required for Reactive patches on your checklist.

Disk Space Estimate for Staging Areas

When you have created a staging area on your local system, you can distribute that staging area to a remote system, provided the two systems match. Both systems must match OS versions, relevant SUBSYS products, and applied patches.

To estimate the amount of disk space required on the remote system for a staging area that resides on your local system:

Log onto the local system.
Start HP Stage/iX.
```
  :STAGEMAN
  STAGEMAN>
```
Execute the disk use command.
```
  STAGEMAN>DU staging_area_name
```
where staging_area_name is the name of the staging area you want to distribute.
The return lists the amount of non-contiguous disk space used by the staging area.
Record the estimated disk space required for the staging area on your checklist.

Converting Between Disk Sectors and MBytes

If your products are listed in MBytes, particularly third-party products, calculate the disk space sectors by performing this conversion:

n Mbytes × 1,000,000 sectors/256 bytes = m sectors

where:

n - the number of Mbytes

m - the number of sectors

Example of MBytes to sectors:

If VALIDATE reports 20 Mbytes total on a tape:

    (20 × 1,000,000)
    ---------------- = 78,125 sectors
          256

Example of sectors to MBytes:

If a disk has a device size of 7,824,336:

    7,824,336 × 256
    ---------------- = 2,003 megabytes
      1,000,000

Therefore the disk is a 2,000 Mbyte disk, (also known as 2 GByte disk).

For a closer estimate, use the value 1,048,576 instead of 1,000,000.

For a quick estimate, use the value 4,000 instead of 1,000,000/256.

Contiguous Disk Space Requirements

The maximum amount of contiguous disk space sectors required to complete a system modification on any system is approximately:

120,000 sectors

Use CHECKSLT to estimate the amount of contiguous disk space sectors required to complete a system modification on your system.

Use DISCFREE to see how much free space you have on your system.

If you are performing an Update with Tape or Modify Remote System task, and you want to have a closer determination of contiguous disk space for AXLDEV1, proceed to Step 1 to determine the disk space required by the UPDATE tool.

Otherwise, proceed to the subsection, "Disk Space Error Messages."

Update with Tape, Modify Remote System

To determine the amount of contiguous disk space sectors required by the UPDATE tool:

Log on as MANAGER.SYS:
```
  :HELLO MANAGER.SYS,PUB;HIPRI
```
Mount the FOS tape.
Restore the CHECKSLT program files, if they were not restored previously:
```
  :FILE TAPE;DEV=TAPE
  :RESTORE &
  *TAPE;CHECKSLT.MPEXL.TELESUP,CKCAT000.MPEXL.TELESUP;SHOW
```
where the 000 are zeros in CKCAT000.

Estimate contiguous disk space required to update your system.

Mount the Factory SLT or remote installation CSLT, as appropriate and run CHECKSLT.


  :CHECKSLT.MPEXL.TELESUP

  **************************CHECKSLT 1.9************************
  --------------------------------
  L E V E L - N U M B E R S
  --------------------------------
  1 - Check the tape. Display errors and file names.
  2 - Check the tape. Display errors, file names and size.
  3 - Check the tape and display all information for each section.
  4 - Recover a TAPE BOOT file. NOT AVAILABLE
  5 - Recover a DISK file from the tape and copy it to a disk file.
  6 - Check the tape and display the contents of one file in hex.
  7 - Check the tape and display summary of tape and disk use
      statistics. 
  8 - Information.
  9 - Exit program.
  
  Which level? __

Select option 7.

Record sectors required for axldev1 on your checklist.

Disk Space Error Messages

The update tools (UPDATE,AUTOINST, HPINSTAL, and Patch/iX) that modify your system require a minimum amount of contiguous sectors within the first 4GB of disk space on LDEV 1 and non-contiguous sectors on the system volume set to ensure a successful modification process. These disk space sectors are a subset of, and are included in, the peak usage disk space requirements. The default disk space requirements are listed below.

Type	Sectors
Contiguous	120,000
Non-contiguous	787,000

The tools search for the default disk space during the modification process. At any point in the process, if the tool does not find the disk space it requires, you may see an error message. The error messages and responses required vary depending upon when they occur in the modification process. For additional information, refer to Appendix C Managing Disk Space and Appendix H Error Messages and Warnings

Estimating Disk Space completed. Go to the next section on your checklist.

3.5 Checking Peripherals

Chapter 4 Preparing Your System