System information

66
AS/400 IBM Network Station: Techniques for Deployment in a WAN
The linear Flash memory supported by the Network Station has the
characteristic that space is allocated in contiguous blocks at the end of
existing used memory. If a file is added or replaced it goes at the end of
currently allocated memory and the memory allocated to the previous version
of the file is effectively lost.
A utility to reclaim unused space is available but it must be started manually
from a command shell locally on the Network Station or remotely by starting a
TELNET session to the IBM Network Station.
The PCMCIA Flash cards are formatted using the format utility that is
supplied with the Network Station software. Files are then copied to the card
using the NFS protocol or by using the local file manager utility on the
Network Station. You can also TELNET to the Network Station and invoke the
local file manager remotely. It takes approximately two minutes per megabyte
to copy data to the Flash card. If the copy process is interrupted, the Flash
card may be left in such a state that the Network Station cannot be booted
from it and the card will need to be reformatted.
Due to these limitations, we recommend that PCMCIA Flash be treated as
read-only memory. While it can be written to by applications (such as a
browser), the fact that space is not easily recoverable means that the card will
fill up and be unusable for further updates until space is reclaimed manually.
3.1.2 Flash Card Management
The management of the data on a Flash card is time-consuming and is not
yet automated. There are no tools provided to synchronize the files on the
Flash card with those on the server or even to indicate when the files on the
Flash card are down-level from some designated configuration. In fact, the
files within the Flash card (local) file system have no timestamps. Therefore, it
is not easy to tell which version of each software module is on the card.
A manual Flash card labelling system should to be introduced to identify
which level of software and which applications the card contains.
To update the card while it is in the Network Station, it is best to first mount
the file system to a server using NFS. Then the new files can be copied (at
two minutes per megabyte) to the Flash card. If the link goes down or the card
fills up, the card may be left in a partially updated state and render the
Network Station unusable until a correctly formatted card is obtained.
For this reason, we recommend that when updates are required, a new Flash
card be sent out to the affected sites. The obsolete cards can be returned to
be reformatted and Flashed again (file copy) at a central location. This makes