Best of Tech Support
Big Drives?
I am running Red Hat 9.0, Fedora 1 and Debian 3.0r4. I have contacted
Intel about running 160GB hard drives. They replied, “The OS is what
determines what size the hard drive can be.” And they quoted Windows 2000
and Windows XP, so I thought maybe the BIOS was involved. What is your
take on this mater, and where can I find references on the subject?
—
Georg Robertson
grobertson29@earthlink.net
The machine's BIOS actually defines certain limits
for hard disks, from the old Int 13 specification for
a DOS (yes, Disk Operating System) capacity limit of
around 8GB to the most modern BIOS and drive hardware
capabilities of 32-bit sector numbers that allow a
theoretical capacity limit of more than 2TB and with
it a whole new challenge for software. Of course, the
OS disk drivers, bootloader, filesystem and probably
other features, such as software RAID, determine the
actual available capacity of a disk drive or set of
disk drives.
—
Felipe Barousse Boué
fbarousse@piensa.com
I often can get Linux working
on strange drive geometries that give Windows fits,
because the kernel can be told what to do with them
manually. There is an excellent guide on just this
topic, and I suggest you start there:
www.tldp.org/HOWTO/Large-Disk-HOWTO.html.
—
Chad Robinson
chad@lucubration.com
Using a Mobile Phone with a USB Cable?
I am able to connect to GPRS mobile devices, including
the Motorola V66 and Timeport, by using a serial
cable. But the latest GPRS mobiles come with only
USB data cables. I tried but was unable to connect
one to a Linux system; I was told the PC could not
find the modem. Can you tell me how to connect it or
suggest suitable drivers for it?
—
kimaya@vsnl.com
These devices almost invariably are still serial but include a USB-to-serial-device chip to provide the USB interface. There are two forms of these conversion chips. One, such as the FTDI chipset, is designed to create a virtual serial port through the USB interface. These products usually already are supported under Linux, and if not, it typically is only a matter of time before this happens.
The second type is proprietary and relies on
custom software drivers that communicate to the
remote chipset. These tend to make portability
more difficult, because manufacturers still
generally release these drivers only for Windows,
and without the driver you cannot communicate with
the device. Fortunately, there are fewer of these,
but because they can be less expensive than virtual
serial port chipsets, some manufacturers will continue
to use them. Your best bet is simply to avoid these
types of products by monitoring newsgroups, forums
and other information sources for Linux user success
stories before purchasing them.
—
Chad Robinson
chad@lucubration.com
Plenty of GPRS phones can be used with Linux; the following Web resources provide a lot of useful information about GPRS phones and their uses. In conjunction with a Linux system, take a look at kotinetti.suomi.net/mcfrisk/linux_gprs.html, users.tkk.fi/~kehannin/bluetooth/bluetooth.html and markus.wernig.net/en/it/usb-serial-handy-ppp.phtml.
I also recommend that you consider using a Bluetooth
wireless interface to link your Linux box, with the
proper adapter and your phone, which hopefully has
Bluetooth capacity.
—
Felipe Barousse Boué
fbarousse@piensa.com
Tuxmobil.org maintains a list of compatibility reports
and how-to documents on connecting using specific
mobile phone models.
—
Don Marti
dmarti@ssc.com
Error from MySQL Client
I am trying to use the GUI MySQL client with Fedora Core 3, but it is failing, returning this:
[anupam@localhost mysqlgui-1.7.5-1-linux-static]$ ./mysqlgui mysqlgui: dynamic-link.h:57: elf_get_dynamic_info: Assertion `! "bad dynamic tag"' failed. Aborted
Any ideas what is wrong?
—
Anupam De
anupam@sail-steel.com.
Did you download mysqlgui in binary form as opposed
to text or ascii? If you transferred text or ascii,
your file may have been corrupted. Alternatively,
try downloading the statically compiled version of the
mysqlgui software package instead of the semi-static
binary. You will get rid of some dependencies, as
the slightly larger executable includes everything
required.
—
Felipe Barousse Boué
fbarousse@piensa.com
Setting IRQs for Serial Ports
I have Win4Lin running on SUSE 9.2 and am having a hard time changing
the IRQ on com port 2. I need Windows for an energy management program
and must call out to check several building systems. Linux has the IRQ
set at 10, but I need to have it set at 4. Can you tell me how to change
the IRQ?
—
John Langston
jdl.28@cox.net
You should be able to change the IRQ in your BIOS settings. If that
doesn't work, use the setserial program on Linux to change this value.
—
Greg Kroah-Hartman
greg@kroah.com
Do a man setserial to learn your command
options. Be aware that if your physical serial ports do have fixed IRQ
and/or memory addresses, you may run into conflicts when playing with
setserial and/or with other devices.
—
Felipe Barousse Boué
fbarousse@piensa.com
GigaDrive Doesn't Work
I recently purchased a Linksys GigaDrive on eBay. The
unit seems to power up and such, but I cannot access
or run any of the applications. I am thinking maybe
the drive has been formatted or replaced and I need
to reload the Linux software and apps. Do you have
any advice on how to do this, other than to send
it to Linksys? I am A+ certified, but I don't have
much Linux experience. I was thinking that if I could
obtain a restore CD, I may be able to rebuild it—is
that true? Of course, if I can do that, I need to
find such a restore CD. Any suggestions or advice?
—
Randy Warner
warn4421@bellsouth.net
There is a page on how to load the GigaDrive's “firmware” on the Linksys site: (www.linksys.com/support/support.asp?spid=17).
If that doesn't work, and you have access to an identical hard drive from a working GigaDrive, you could make a bit-for-bit copy by hooking the working drive up to a Linux box as master and the nonworking drive as slave on the secondary IDE interface and doing:
dd if=/dev/hdc of=/dev/hdd
—
Don Marti
dmarti@ssc.com
Backing Up a Dual-Boot System
I currently use Microsoft Windows XP Pro with the intent of migrating to Linux after I get used to running it and administering it. The current backup software I use is Norton Ghost from System Works 2004.
I tried installing Fedora Core 1, as it came free with a book I bought. Installation went without a hitch, and I liked what I saw and used. But, when I boot back to Windows to use Ghost, Ghost gives me this error message:
Back-up Failure. Not space in the MBR.
I said, “forget Norton, I'll do my backups with Linux.” But I haven't the
faintest idea what to use on Linux. Any suggestions?
—
Lev Ranara
pinoy_techie@yahoo.com
Backups under Linux are usually straightforward. Unlike Windows, there is no special system data (registry or system configuration) that cannot be copied through traditional means. A straight file copy, in fact, usually is sufficient for a “complete” backup, unless a database server is running. In this case, it may need to be shut down during the backup.
Complex solutions abound and allow managed, catalog-style backups and restores of individual files. These are available as free software (such as Amanda and Bacula), from traditional vendors of Windows backup software (VERITAS, CA and so on), as well as from some vendors specifically focused on Linux (such as BRU). However, since you're using Ghost, it sounds like you're not really doing file-based backup anyway. The simplest solution thus would be a compressed tar archive. Restoring the entire system then is a simple matter of partitioning and formatting the drive, extracting the archive and re-installing the boot loader.
If that's true, start with tar and see if it suits your purposes. A command such as:
tar -jlcvf /tmp/mybackup.tgz /bin /boot /dev /etc \
often suits the most basic needs. Then, simply copy /tmp/mybackup.tgz
onto CD, tape or another server. You also can tar directly to tape.
—
Chad Robinson
chad@lucubration.com
My best experiences in the Linux backup world come from using the good old tar command, the compression utilities such as zip and bzip, and some scripts I have written for each specific backup need. It's reliable, portable, straightforward and free—freedom and money-wise. For more information, see www.linux-backup.net for everything related to Linux and backups. The book Unix Backup and Recovery also deals with the subject; it was reviewed on LJ at /article/3839.
Also, try installing FC3 as FC1 is now deprecated. FC# has a lot of nice
features such as drag and drop to burn CDs, which may be useful for
backups.
—
Felipe Barousse Boué
fbarousse@piensa.com
Client Connects, but TFTP Fails
I'm trying to get my TFTP server running properly, and I'm not having any luck figuring out the problem. Here's the scoop. I'm running Fedora Core 3 on a PIII machine. I've installed the latest tftpd server from rpmfind.net, and have configured xinetd/in.tfptd properly (I think). Using a tftp client on another Linux machine, I can connect to my tftp server, but the read requests go unanswered. The client times out after several retries. In /var/log/xinetd, I see the following entries for each read request sent by the client:
05/3/16@14:11:14: FAIL: tftp address from=153.90.196.30 05/3/16@14:11:14: START: tftp pid=20184 from=153.90.196.30 05/3/16@14:11:14: EXIT: tftp pid=20184 duration=0(sec)
Here is what I've done to configure the server. I created a user tftp with home dir of /tftpboot and ran /sbin/nologin. I added an entry to /etc/hosts.allow of in.tftpd:ALL. I created a directory /tftpboot with correct permissions and ownership. I then created the file /etc/xinetd.d/tftp with the following contents:
service tftp { disable = no socket_type = dgram protocol = udp wait = yes user = root server = /usr/sbin/in.tftpd server_args = -s /tftpboot -u tftp per_source = 11 cps = 100 2 flags = IPv4 #only_from = 153.90.196.30 }
I've tried this with only_from both commented and uncommented. I've also made sure that the firewall trusts UDP and TCP on port 69. I verified that the contents of /etc/xinetd.conf are correct, and I verified that tfptd is running via chkconfig. I also verified that port 69 is available via netstat. I've tried running in.tftpd in standalone mode (server_args = -l).
I've been working on this problem for three days and am getting no where.
I'm something of a newbie to Linux, but I have asked more experienced
folks for insight to no avail and have spent hours trying find instances
of this problem on the Internet, also to no avail. So, I'm hoping you
folks can point me in the right direction.
—
Todd Trotter
ishamt@esus.cs.montana.edu
It seems as though you have done almost everything correctly. Some issues come to mind though. First, change the user to nobody on the file /etc/xinetd.d/tftp; otherwise, the in.tftpd dæmon runs as root, which is not safe.
Second, make sure the lines:
tftp 69/tcp tftp 69/udp
are not commented out in the /etc/services file. Also, I suggest checking the file /etc/hosts.deny to see if you are blocking requests for the in.tftpd dæmon, for all services or for requests from a specific IP (client machine).
For testing purposes only, make sure this file is empty, reload xinetd
(service xinetd reload) and try again. Also, for testing only, turn off
your firewall (service iptables stop) and test again. Test and make your
setup work locally by issuing tftp localhost before testing remotely.
Hope this helps.
—
Felipe Barousse Boué
fbarousse@piensa.com
Is Garbage Collection the Answer?
I learned about garbage collection (GC) from your journal. I do have a problem. Let me explain the situation that exists. Initially, the project occupies 192MB of RAM in Linux. It was allowed to run continuously. Then, after 12 hours, we noticed it was using 335MB. What is the solution for this problem? Is it due to garbage? Will the BDW garbage collector provide a solution? The project includes char pointers, and it doesn't include any malloc functions.
Will BDW GC work only if we include malloc, calloc
or realloc functions? Can I have a program that runs
along with my project and releases free memory?
—
Mythily J.
mattuvar@yahoo.co.in
The answer to the last question is no. Unless you do really hairy and hard-to-debug things, only your program can free memory that it allocated.
The others are really good questions, and the only way to know for sure is to try it with your code. Even though you may not be using the malloc family of functions, you might be making library calls that allocate memory and then omitting some of the calls required to free it.
The good news is that you can build a version of
your program that uses GC for all memory management,
including memory allocated in library code, by
“hooking” it in to malloc. See Listing 1 in this
article: /article/6679
for an example.
—
Don Marti
dmarti@ssc.com
Runlevel Editing
In the April 2005 Best of Technical Support, in “Old Red Hat”, Timothy Hamlin suggests changing the /etc/inittab entry from:
x:5:respawn:/etc/X11/prefdm -nodaemon
to:
x:3:respawn:/etc/X11/prefdm -nodaemon
to suppress the X graphical login. I think he made an error here. His reply will launch X at runlevel 3. Instead change:
id:5:initdefault:
to:
id:3:initdefault:
to change the default runlevel.
Also, in “Tweaking inodes and Block Sizes”, Don Marti points out that
Red Hat 9 is no longer supported and that this might be an issue for an
older 486 system. The bigger issue is the amount of RAM Red Hat requires
for the install. I'm not sure if it will install with 32MB of RAM.
It definitely won't with 16MB, which is what my old 486 laptop had.
—
Roland Roberts
roland@astrofoto.org
Either inittab change will work. The second
has the advantage of preserving the “runlevel
5 is GUI login” tradition that Red Hat users
are used to. The Fedora release notes at
fedora.redhat.com/docs/release-notes/fc3/x86
list a Pentium as the minimum processor and 64MB as
minimum memory for a text install. (See the last
letter for an alternate approach.)
—
Don Marti
dmarti@ssc.com
What about Fedora Legacy?
In the April 2005 Best of Technical Support, Don Marti writes that
“Neither Red
Hat 9 nor Red Hat 6.2 is still supported, which means
no more security updates.” Although Red Hat has
dropped support for Red Hat 9, the community-based
Fedora-Legacy Project (www.fedoralegacy.org)
is working to provide security updates for Red Hat 9
as well as Red Hat 7.3 and Fedora Core 1 and (soon) 2.
Mr Marti does the project a disservice by ignoring
its efforts.
—
John Dalbec
jdalbec@cboss.com
At the time we went to press, Fedora Legacy was not
actively releasing security updates.
—
Don Marti
dmarti@ssc.com
The Best of Technical Support column in the April 2005 issue of LJ contains some incorrect and incomplete statements in response to a user who wants to use Red Hat 9 on 486 computers. Don Marti writes, “[Red Hat's] successor, Fedora, requires a Pentium or better...No matter what you install, this class of machines will be too slow for a modern desktop.” The RULE Project (www.rule-project.org) proves this wrong. One year ago, I ran Red Hat 9 on a Pentium I laptop with 32MB of RAM. Thanks to it, I used KOffice to make a presentation and Firefox for home banking: www.rule-project.org/article.php3?id_article=55 (see the linked screenshot).
Less than one month ago, we announced a version of our installer for Fedora Core 3: www.rule-project.org/breve.php3?id_breve=19.
Now, it certainly is true that full-fledged KDE, GNOME
or OpenOffice.org installations under any desktop can
be painfully slow, even on much newer computers. It is
equally true that video editing or 3-D gaming requires
state-of-the-art hardware. But, if by modern desktop,
one means modern SOHO functionality—IMAP, digital
signatures, HTML4/CSS support, CUPS, IM, Bayesian spam
filtering, regardless of eye candy—there is no need
to spend money. All it takes is a project such as RULE
and efforts made on things such as mini-KDE. In any
case, it is possible to run a modern, mainstream
distro on slow hardware, with a bit of care and the
right approach to the problem.
—
Marco Fioretti
mfioretti@mclink.it