tips and techniques

core file limits
A core file is an image of a program's memory that is written to your hard disk when the program crashes. The maximum default size of a core file is 16 MB. 

If there is a /cores directory when a program crashes, the core file is placed in that directory. Because there is no /cores directory on NeXT computers when they are shipped, core files can get dumped in unexpected places. Because core files usually take up a lot of space, it's usually best to delete them if you find them on your disk. (Core files are named core.nnnn, where nnnn appears to be a random number. It's actually the process ID number.) 

To manage core file space on an ongoing basis, you can create a /cores directory and clean it out frequently, or you can decrease the core limit. To set the core limit to 0 instead of 16 MB, you need to start up the Terminal application and enter 

	dwrite Workspace CoreLimit 0

using e-mail
NeXTmail? is, we think, one of the great advantages of NeXT Interpersonal Computing. Work groups using NeXTmail can achieve new levels of productivity through the multimedia NeXTmail environment. The following tips about NeXTmail should help you reap the full benefits of e-mail and avoid problems.

frozen configuration files 
It's sometimes useful to modify sendmail 
configuration files. However, a frozen sendmail configuration file-which is like a compiled version of a sendmail configuration file-will crash sendmail. NeXT software does not automatically create frozen sendmail configuration files. If you are logged in as root, running sendmail with the -bz option will create a frozen sendmail configuration file (/etc/sendmail/sendmail.cf) which, in turn, will cause sendmail to crash with a bus error. 

To remove the frozen configuration file you also need superuser privileges. Either log in as root and drag /etc/sendmail/sendmail.cf to the recycler or su to root in a shell and use the UNIX command rm (see NeXTanswersä mail.424).

compacting or undeleting empty mailboxes
Don't compact a mailbox that is already empty or use Undelete on an empty mailbox (that is, a mailbox with no message to undelete). Doing so can cause NeXTmail to crash.

repeating read receipts
When a sender requests a "read-receipt," NeXTmail automatically notifies the sender when the recipient reads the message. Be aware that repeat receipts can be generated when read-receipt messages are transferred to and reopened in different mailboxes. 

Courier, Ohlfs, and non-NeXTmail
If you've set non-NeXT mail as your default in mail preferences, don't also set Ohlfs or Courier as your default font. Doing so results in several problems when sending mail, such as faulty mail attachments.