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Problems Mapping Drive to AS/400

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by bds19591

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I am trying to map a network drive to an AS/400 folder. This is being done successfully to other folders on the AS/400, and also to this particular folder with this particular user. However, the mapping intermittently breaks. I've been able to "fix" the mapping in the past, several times, however, now I'm not able to get it to work on the user's PC. Just to double-check things, although it took multiple attempts, I was able to successfully do the mapping on MY workstation. That would appear to me to show that security, etc., is set-up correctly on the AS/400 side. However, again, at the user's end, this time I am having no luck. To reiterate and/or clarify, this HAS worked on this user's PC - however, again, it will work for some period of time, then, when he goes to open the mapped drive, it's not connected; the map is broken. I've been able to re-map the last two or three times, however, it's always a process; it's never easy. My theory is that there's something in Windows that's causing the problem, however, I'm not positive about that, and I have no idea where to start looking. As as side note, this is in some ways a more general problem; although we do have numerous users that have folders mapped on the AS/400, we have had quite a few problems doing the mappings, and, having them not break. The OS is Windows XP, SP3. Any help would be greatly appreciated.

4 replies

by robo_dev

I assume that this is the simple 'map network drive' function and that 'reconnect at login' is checked? Or is this a shortcut to a share?

There are settings in Windows that allow drive mappings to timeout. The default time is 15 minutes.

Mapped Drive Connection to Network Share May Be Lost
http://support.microsoft.com/kb/297684

A shortcut to a Windows share generally does not timeout, as long as the PC is connected to the network, in my experience, but network mapped drives do.

All this stuff can be intermittent for several reasons:

Microsoft uses SMB protocol to do all this mapping and sharing.

SMB is broadcast-based, and if the LAN is very busy, SMB is both the culprit and the victim in terms of connectivity issues. SMB is so chatty that it can use a lot of bandwidth, and it's a bit fragile, so it can have problems on busy networks. As a network person, the first thing I would do is check the user's network connection: make sure their ethernet connection is not dropping packets, which could happen if the link were mis-negotiated to half-duplex or their NIC is failing.

SMB also relies on doing periodic updates, doing stuff like 'browser elections' and updates of what SMB devices are known to each other. SMB is more magic than technology, and can be somewhat tricky to troubleshoot without resorting to a protocol analyzer such as Wireshark.

The other issue is that if the Windows PC is set to standby, waking up is not always a clean process, as the SMB communication has to catch-up, which takes a minute or so. Ideally, Windows network PCs should never go to standby or hibernate.

by david.asher

I am also having the same issue. A little differnet but the same output. We are mapping two folders on the as400 to two drive letters with the same user from the as400. One will map and the other will not. Will map if I run my vb script from my local pc but will not map when I log on. Also, I will get an access denied everyonce and a while. Stupid and sporadic.

by robo_dev

Is that something OS/400 can do natively, or are you using a 5250 emulation program on the PC of some sort?

In general, whenever another OS tries to emulate a capability of a different OS, it works great during the sales presentation/demo but not so much everyday.

In this case, OS/400 is emulating not only the Microsoft SMB protocol, but also the Kerberos authentication and Active Directory that's part of Windows. These protocols do not work all that well on Windows server, so on OS/400 I would not expect too much.

Assuming that IBM does know how to make this work:
a) look for OS patches and bug fixes around this, surely there are.
b) fire up a protocol analyzer such as WireShark, as many SMB issues are really LAN issues (broadcast traffic storms, over-subscribed uplinks, etc)

If IBM does not know how to make this work, then I would explore using a different protocol such as FTP or NFS...those tend to be reliable on any OS.

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