benc's questions

Solaris 10 using snoop to capture packets.

When I telnet to an unused IP address, and wait for the connection attempt to time out, everything behaves as expected (SYNs sent several times until connection establishment time out exceeded, then telnet quits).

When do the same thing, but cancel the attempt before it reaches the time out, with control-c, the last packet has a RSET.

Is this done for a reason? Maybe the network stack is assuming that the SYNs were successful, even if the SYN-ACK didn't come back, so it sends a RSET to keep the remote system from being left half-open?

I had read Stevens TCP/IP Illustrated, Vol 1 a long time ago, and I don't recall this being discussed (I checked with a quick google, but didn't dig up the book).

I have a reasonably large set of data in an LDAP server. Some of the attributes appear in many places, and I would like to replace them.

The data is not enormous, but it is enough to rule out editing and export manually.

What's the best approach for this? Use an LDAP tool to find and replace them? Write a script to modify the entries? Export data and edit it locally?

Any suggestions would be helpful.

I need to run some Outlook sessions that connect to an Exchange server. If I wanted to create a test environment on my laptop, would that be feasible? Would it be better to run natively, or inside a VM?

(I had heard some commments, probably from the Stackoverflow podcast, that Exchange designed to run by itself).

I might need to run only the latest, or I might need to run several versions. Can I load them on one system in parallel, and switch them on-and-off?

UPDATE: The hypothetical system would have a 64bit CPU, and 4GB of memory.

Solaris 10, SPARC.

While trying clean up my "/opt" directory, I saw the "sun_docs" directory.

I scanned the contents with "du -a", and also found a single, possibly related file (/var/opt/sun_docs/sundocs.html).

If I understand correctly, it looks like a local set of HTML files, designed to be ready by a locally running browser? It looks like it could be shared via http, if an admin knew how to turn that on.

I did google and check docs.sun.com.

-ben

This might not be answerable in theory, but any thoughts are appreciated:

I have a UNIX server that has 2GB of RAM, and presumably it is slightly overloaded and swapping to disk heavily. It is a test server, and the only user is me, so being busy is not a problem.

I have some extra RAM available (lets say 6GB) of RAM. Assuming the RAM upgrade substantially removes the need to page to disk, the question I have is:

Will the upgrade save energy (from a net reduction of disk usage vs. the energy used by the additional RAM)?

UPDATE: To clarify, this is not a "save $$$" question, this was a curiosity. Joel had once made a comment in a podcast about how there is always someone asking if they can run their system with lots of RAM and no swap, because they have a simplistic view of how memory is managed. This was me, thinking about the ways adding RAM would change my system's behavior.

Recently, some discussions came up about 32 bit vs. 64 bit implementations of operating systems.

While I was composing a message about this topic, I realized that I did not know if there was a correct term for the number of bits supported by an operating system.

For example, various versions of Solaris and Linux have 32bit and 64bit releases. Is the distinction "architecture"? In my experience, that has referred to chip types (Intel vs. PPC). Is it a "release"? Typically, I think of a release as a version number a consistent feature set, that might run on different architectures.

Maybe it is just "architecture", after all, even though a chip family might have used several different bit sizes over time, the chips themselves are different when you jump from 32bit to 64bit.

When you read the man pages on Mac OS X, there are references to /var/log/messages, but if you look for the file, it doesn't exist:

$ ls -l /var/log/messages
ls: /var/log/messages: No such file or directory