IBM z/OS - Manual (Page 11)

11
Although CBU and On/Off Capacity on Demand can both
reside on the server, the activation of On/Off Capacity
on Demand is mutually exclusive with Capacity BackUp
(CBU) and no physical hardware upgrade will be sup-
ported while On/Off Capacity on Demand is active.
This important new function for zSeries gives customers
greater control and ability to add capacity to meet the
requirements of an unpredictable on demand applica-
tion environment. On/Off CoD extends zSeries capacity
on demand offerings to the next level of fl exibility. It is
designed to help customers match cost with capacity
utilization and manage periodic business spikes. On/Off
Capacity on Demand is designed to provide a low-risk way
to deploy pilot applications, and it is designed to enable a
customer to grow capacity rationally and proportionately
with market demand.
Customers can also take advantage of Capacity Upgrade
on Demand (CUoD), Customer Initiated Upgrade (CIU),
and Capacity BackUp (CBU) which are described later in
the document.
The z990 has also been designed to offer a high perfor-
mance and effi cient I/O structure. All z990 models ship
with two frames the A-Frame and the Z-Frame; this sup-
ports the installation of up to three I/O cages. Each I/O
cage has the capability of plugging up to 28 I/O cards.
When used in conjunction with the software that supports
Logical Channel SubSystems, it is possible to have up to
420 ESCON ® channels in a single I/O cage and a maxi-
mum of 1024 channels across 3 I/O cages. Alternatively,
three I/O cages will support up to 120 FICON ™ channels
and up to 360 ESCON channels. Each book will support
up to 12 STIs for I/O connectivity. Seven STIs are required
to support the 28 channel slots in each I/O cage so in
order to support a fully confi gured three I/O cage system
21 STIs are required. To achieve this maximum I/O con-
nectivity requires at least a B16 model which provides 24
STIs.
The following chart shows the upgrade from z900 to z990.
There are any to any upgrades from any of the z900 gen-
eral purpose models. A z900 Coupling Facility Model 100
must fi rst be upgraded to a z900 general purpose model
before upgrading to a z990. There are no upgrades from
9672 G5/G6 or IBM ^ zSeries 800 (z800).
Model Upgrades
z900 z990
100
101 - 109 A08
B16
C24
D32
1C1 - 116
2C1 - 216