CD-R/W discs can be written with a technique called packet or incremental writing. This allows transparent and buffer-underrun-free recording for CD recorders that support this method. No more mastering of .iso images; just mount your CD-ROM read/write and copy files directly to it.
iSCSI Linux Initiator Driver is a kernel module for use with linux-2.4.x. This module provides client-side support for iSCSI. iSCSI is an IETF draft desribing SCSI encapsulation over TCP/IP. This release was written to version 3 of the draft. The drive is architected as a lower half adapter driver. Do not use SCSI devices with important data on the target side.
The ip-masq-log patch can be used on a masquerading firewall (NAT) to keep a log of all the outgoing masqueraded TCP connections. It's even possible to log the name of the user who has opened the connection. This can be a useful security tool for many small networks that are hidden by a masquerading box if users cannot be totally trusted.
UDI, the Uniform Driver Interface, is a well-documented interface between a driver module and the executing OS. It provides source portability across OSes and binary portability within a processor ABI. It also provides modern driver features like instance independence, high scalability, and physical location transparency. The Reference Source provides an initial implementation of UDI for Linux, SCO UnixWare, SCO OpenServer, and other OSes.
TUN provides packet reception and transmission for user space programs. It can be viewed as a simple Point-to-Point or Ethernet device, which instead of receiving packets from a physical medium, receives them from a user space program and instead of sending packets via physical media writes them to the user space program.
The Yoke driver provides transparant mirroring between disk partitions and other block devices (such as loop and nbd). It differs from the kernel RAID0 facility in that it is a virtual device with no interface of its own. To start mirroring one device to another requires no prior setup, just "yadd /dev/yd0 yet_another_device" and go. The yet_another_device will become another facet of the existing mirror and you can still read and write to it perfectly normally, with the difference that all changes will be seen and reflected in/from all the other mirror facets.