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Hi! I would like to thank you for doing so interesting a journal. It's my second subscription to LJ, and it won't be the last. I found the XForms review and tutorial so interesting that I decided to test it and will, perhaps, even use it at work. I enjoy reading tutorials and explanations about the Linux kernel (thanks a lot to Michael K. Johnson and all the staff of Linux Journal).
You try to spread the Linux enthusiasm everywhere. It's a success. Thank you.
Eric Bouchut
Juergen Schmidt, an attentive reader, reported a few errors in the third Kernel Korner article about device drivers, co-authored by Georg van Zezchwitz and myself. The errors are my fault, due to the limited time I had to revise the article.
The code printed within the article comes from a real driver, and it is known to run, but sometimes, I forgot to substitute the name of a symbol while copying from the real driver to the article's text.
So, Skel_Board (the structure) should read as Skel_Hw; hwp (the pointer) is equivalent to board (replace either one with the other); in skel_select, file (the struct file pointer) should read filp.
I'm sorry for these inconsistencies, and I hope they didn't cause headaches to the readers.
-- Alessandro Rubini rubini@foggy.systemi.it
I have a few corrections to my article Building a Linux Firewall in LJ #24, April 1996, page 49.
1) Figure 3 is a duplicate of Figure 2. This is my fault. I submitted it this way. Obviously, cut-and-paste from one xterm to another can either be your friend or your enemy. I must have copied from the wrong window. The correct contents for the figure are shown here:
# ipfw -n list b Type Proto From To Ports deny udp anywhere 192.168.1.1/32 any -> any deny udp anywhere 20.2.51.105/32 any -> any accept udp anywhere 20.2.51.105/32 domain -> any accept udp 20.2.61.0/24 20.2.51.105/32 any -> snmp deny tcp anywhere 20.2.51.105/32 any -> any deny tcp anywhere 192.168.1.1/32 any -> anyFigure 3. New blocking rule for SNMP to only accept from 20.2.61.0.
I've squeezed that down. Please use a condensed courier font to make it fit, or somehow make it a wide inline figure.
2) Several of the ipfwadm commands on page 58 have an additional character within the command line. The character is a right angle bracket, and this could cause some undesirable side effects if typed in that way.
3) The sentence on page 53 ``ipfw only supports the deny and accept policies, not reject.'' should be corrected to, ``ipfw only supports the deny and accept policies for its output. A rule set to reject will still show up as deny.''
-- Chris Kostick cykostick@csc.com
During the Space Shuttle mission STS-75, an astronaut was heard talking about the fact that Linux was installed on a computer on board the spacecraft. A few weeks later, the computer's function was disclosed. The software in use was X-based software developed under Digital Unix and ported to Linux so that it could be used on board the shuttle. Astronaut Ron Parise said in an e-mail message to fellow amateur radio operators:
Pat, et al.:
Linux was installed on one of the IBM Thinkpads that are usually flown on the shuttle. This was in support of the tether experiments. Since the ground-based applications to control those experiments ran on a DEC Alpha it was easy to just port them to a Linux system for on-board use.
73's, Ron WA4SIR