Calculating Cache Size For Mainframe Systems - HPE XP7 User Manual

2. Calculate the number of addresses between the starting address and the ending address
calculated in step 1.
1. For OPEN-V:
Number of addresses = Converted value of ending address -
Converted value of starting address + 1
Calculate the number of LBAs that are used by the user data.
2. For emulation types other than OPEN-V:
Number of LBAs = Converted value of ending address - Converted
value of starting address + 1
Calculate the number of LBAs that are used by the user data.
Number of slots = Number of LBAs / 96
Convert the number of LBAs to the number of slots.
Number of addresses = Number of slots × 128
Convert the number of slots with 128 LBA.
3. Calculate the required cache size according to the operation mode to use Cache Residency.
1. When bind mode is set:
Required cache = No. of addresses × (512 + 16) × 3 / 1,024
The unit is KB.
2. When priority mode is set:
Required cache = Number of addresses × (512 + 16) / 1,024
The unit is KB.
If the area is changed from priority mode to bind mode and no cache is added, then only 33%
of the user data will fit in the area previously assigned for priority mode, and the remaining 67%
is used to save read/write data.
CAUTION:

Calculating cache size for mainframe systems

You can calculate cache size for mainframe systems.
Procedure
1. Calculate the converted number of slots. To calculate the number of slots as converted from
the specified starting address and ending address, use the following formulas:
Converted value of starting address = Setting value of starting
address (CC) × 15 + Setting value of starting address (HH) where
Setting value of starting address (CC) and Setting value of starting
address (HH) are the values entered in the Operations box of the
Cache Residency window.
Converted value of ending address = Setting value of ending address
(CC) × 15 + Setting value of ending address (HH) where Setting value
of ending address (CC) and Setting value of ending address (HH) are
the values entered in the Operations box of the Cache Residency
window.
Number of slots = Converted value of ending address - Converted
value of starting address + 1
If the area is changed and no cache is added, set the Cache Residency again.
Estimating cache size for Cache Residency 143