Study Notes

Yesterday, completed reading the RHCE(7.3) documents, and started up RHCE(3.0) compaign.
Plan to 3 days. The next one is RedHat Manual.

What time is the best to take RHCE exam? Today, I’m really annoyed this problem, since I decided to get RHCE cert in Octorber. In recent two months, I insist on reading Study Guide every night, and do not finish the course now. Sometimes I feel anxious and a litter disapointed.

I call some exam companies this afternoon, who told me an exam arranged in 29th Jan, 2007 and the fee is 4300 excluding training cost. I think it’s too expensive to have such a training only for rapid passing exam(Training+Exam=8100 in Shenzhen, and 6000 in Guangzhou). If join such “rapid-training camp” and even pass RHCE very easily. is it really benifit for me? Do I only need such an paper to declair how clever I am, or just depend on it to get a better job? Do I really master the study points of Linux world?

Absolutely not. It wastes my money and violates my rule to become a Linux professioner. I perfer to take more time to perpare, read more carefully, do more experiences, and recite the key knowledges by writing them on papers. Till all is ready and I feel confident, I directiva take exam without joining training. It will save me a lot of money and make my heart more stronger.

Go ahead, with more patience.

It tooks about two days on resolving how to update kernel 2.6.19.1 in VMware5.5, because the VMware default configured disk is SCSI which need some special module setting. During this course, I learn more about kernel concepts.

1. Target
Update the lastest kernel 2.6.19.1 in VMware5.5 in order to research NFSv4.0

2. Test Environment
VMware version: 5.5.1 build -19175 for linux
Virtual Operating System: CenOS 3.5 (Kernel 2.4.21-32EL)

3. Steps
Install Virtual Operaing System CenOS3.5 which kernel is 2.4.21. Download the kernel 2.6.19.1 with related patch from www.kernel.org.
# cd /usr/src
# tar xvf /download/linux-2.6.19.1.tar
# ln linux-2.6.19.1 linux-2.6
# cd linux-2.6

Apply the patch:
# bunzip2 -dv /download/patch-2.6.19.bz2 | patch -p1

Begin to compile:
# cd /usr/src/linux-2.6
# make mrproper
# make menuconfig (make oldconfig would be ignored here)
At this point, the following items must be selected as “build in”, more explanation would be wrote in the later section.
SCSI device support <*>
SCSI device -> SCSI low-lever device -> Buslogic SCSI support <*>
Device Drivers -> Fusion MPT sevice support <*>
Device Drivers -> Fusion MPT (base+scsihost) drivers <*>
Device Drivers -> Fusion MPT (ioctl) drivers <*>
Device Drivers -> USB support <*>
Device Drivers -> Network support -> Ethernet(10/100) support <*>
File System -> EXT2, EXT3 support <*>
Commend, the vmware default SCSI controller is Buslogic.

If not add “scsi, usb, mpt” built in directly, or just select modules load [M], when issue “mkinitrd /boot/initrd-2.6.19.1.img 2.6.19.1”, there’s the following error message:
no modules mptbase found for 2.6.19.1 kernel, aborting
If not add “ext2, ext3” build in directly, or just select modules load [M], when reboot after compiling, the system will be halt:
Kernel Panic: no init found

Continue the compiling process:
# make bzImage
# make modules
# make modules-install
# cp /usr/src/2.6.19.1/arch/i386/boot/bzImage /boot/vmlinuz-2.6.19.1
# mkinitrd /boot/initrd-2.6.19.1.img 2.6.19.1
# cp /usr/src/2.6.19.1/System.map /boot/System.map-2.6.19.1
# cp /usr/src/2.6.19.1/.config /boot/config-2.6.19.1

Modify “/boot/grub/grub.conf”:
# This is Phillip’s /boot/grub/grub.conf
default=0
timeout=10
splashimage=(hd0,0)/grub/splash.xpm.gz
title CentOS-3 (2.4.21-32.EL)
root (hd0,0)
kernel /vmlinuz-2.4.21-32.EL ro root=LABEL=/
initrd /initrd-2.4.21-32.EL.img
title New-Kernel (2.6.19.1)
root (hd0,0)
kernel /vmlinuz-2.6.19.1 ro root=LABEL=/
initrd /initrd-2.6.19.1.img
Save and reboot, if all succeed, issue “uname -r” will shows: 2.6.19.1

4. Summary
If set hard disk as IDE, it would be very easy to update. But I think practise on this SCSI system is very benifit for future works. At first begining, when issue “mkinitrd /boot/initrd-2.6.19.1.img 2.6.19.1” and error “no modules mptbase found for kernel”, I just did a stupid thing, add the “–omit-scsi-modules”(ignore scsi), but this system is based on SCSI drivers! Though “mkinitrd –omit-scis-modules /boot/initrd-2.6.19.1.img 2.6.19.1” passed, the system was kernel panic when reboot:

VFS: Cannot open root device “sda1” or unknown-block(0,0)
Please append a correct “root=” boot option
Kernel panic: not syncing: VFS: unable to mount root fs on unknown block(0,0)

By reading some documents, I tried to comment all lines contains “mpt” in /etc/modules.conf, the same kernel panic happenes; Download the latest “lvm2, device-mapped, mkinitrd” rpm packages, however, these packages can not be installed. The only way fixed this problem is building mpt,scsi,ext2,ext3,usb directly when run “make menuconfig”.

menuconfig options:
[*] build-in
[M] modules
[ ] excluded

5. Fix issues in new 2.6 kernel
The network device eth0 seems to be disappeared in new kernel, when execute “#lsmod”, there’s the following error:
QM_MODULES: Function not implemented.

I fix this issue by installing new mode-init-tools(need download),
# cd mode-init-tools
# ./configure –prefix
# make moveold
# make
# make install
Generate “/etc/modprobe.conf” :
# ./generate_modprobe.conf /etc/modprobe.conf
# depmod 2.6.19
OK, reboot the OS, and issue “#lsmod” again, the eth0 module “pcnet32” is listed.(vmware default eth0 module is called pcnet32). Fixed.

In some cases, I need to log in as remote X client, for example, run ConsoleOne in localhost.

Method 1:
System1# ssh -X system2
System2# run any X command you’d like have and it’ll show up on System1
I verifies this way to open remote ConsoleOne GUI(192.168.123.33, nds server) in local(192.168.123.32).
Localhost 192.168.123.32# ssh -X 192.168.123.33
NDS sev 192.168.123.33# ./usr/ConsoleOne/bin/ConsoleOne

Note, that is that does not work it’s because you have X11 forwarding turned off in your ssh config file(perhaps in /etc/ssh/sshd_config).

Method 2:
System1# xhost -system2
System1# telnet system2
System2# export DISPLAY=system1:0
System2# run X command you’d like have and it’ll show up on System1

–display Server:0.0
Send output to the Xserver running on Server.

Xterm is an X-client application that creates a terminal windown on your X-display

Mobo: the abbreviation of MotherBoard.

In my virtual CentOS, try to apply its OpenLDAP installed. First, check “/etc/openldap/slapd.conf”, it used “ldbm” instead of Berkeley DB “bdb”, set the base DN, password and thus configuration is completed. I add a lot of entries for validation, and later delete them. Note, here the destination in “ldapdelete” command must like the following:

# ldapdelete -x -v -D “cn=root,dc=plasmon,dc=sit” -w hello123 uid=inter,ou=People,dc=plasmon,dc=sit

Before the term “uid=inter” there’s no “dn:”, if such title exists, the ldapdelete would get failed.

I want to browse Internet pages via lynx, but now lynx do not support gb2312 directly. So, I did a very interesting test, resolve this issue fairly well.

1. Test Environment
CentOS 3.5, no install X-Window
cce rpm package

2. Recompily kernel to increase the running speed(because it has PIII and only 128MB memory).

# cd /usr/src/linux-2.4.21-32.EL
# vi Makefile
Here, in the line 4, change the EXTRAVERSION to “EXTRAVERSION=-32.ELhx”
# make mrproper
# make oldconfig
# make menuconfig
remove the unuseful components
# make dep
# make bzImage
# make modules
# cp /usr/src/linux-2.4.21-32.EL/arch/i386/boot/bzImage /boot/vmlinuz-linux-2.4.21-32.ELhx
# make modules_install
# mkinitrd /boot/initrd-2.4.21-32.ELhx.img 2.4.21-32.ELhx
# cp /usr/src/linux-2.4.21-32.EL/System.map /boot/System.map-2.4.21-32.EL
# cp /usr/src/linux-2.4.21-32.EL/.config /boot/.config-2.4.21-32.ELhx

Final step, add corresponding lines in /boot/grub/grub.conf. Then reboot.

3. The new kernel starts up very quickly, That’s what I want. Download cce and install this rpm file.
# rpm -ivh cce-xxx.rpm
Then execute “cce” in the command line, and type “lynx www.tom.com”, a famous Chinese site.
Yeah!I got it, all Chinese characters display very beautifully. cce also supports Chinese input, but what types can not be recognized by human for mess code set.

PS: copy cce package from windows to my Linux, and issue “rpm -ivh”, it said the md5sum failed. Download cce in linux, and installed successfully. It seems there’s different md5 checking code in Windows and Linux. I can not confirm.

It sounds to be very annoyed to import posixAccount, shadowAccount attributes and objectclasses in last article. Now I find a easy way. Located the “rfc2307-usergroup.sch” file in “/opt/novell/eDirectory/lib/nds-schema”, issue:

# ndssch -h 192.168.123.33 -t Plasmon cn=PlasmonAdmin.o=Plasmon rfc2307-usergroup.sch

The job would be done well. and then just use ConsoleOne to import “samba-nds” as rename it to ldif file.

To get the OpenLDAP schema entries:
# ldapsearch -x -D “cn=root,dc=plasmon,dc=sit” -w hello123 -b cn=subschema -s base + -H ldap://192.168.123.33:389
In OpenLDAP slapd.conf, it was set as “cn=subschema”, while in Iplanet, it is “cn=schema”.
To get the Iplanet schema entries:
# ldapsearch -x -b cn=schema -s base+ -H ldap://192.168.123.33:389

Assume that do not know the LDAP server type, issue the following command to find it is “cn=schema” or “cn=subschema”:
# ldapsearch -x -H ldap://192.168.123.33:389 -s base -b “” “objectclass=*” subschemaSubentry

Iplanet history: Iplanet 4.0 — Iplanet 5.0 — Sun One Directory Service — Sun Java System Directory Service 5.2

To understand 100Mb/s throughout. Servial factors must be consided. With a 16-bit data bus, two byte are transmitted per bus transation. Thus to achieve a throughout of 100Mbytes/s, the data bus must be clocked at 50MHz. To minimize strobe design complexity, Ultra ATA uses a “double data rate” or double-edge clocking mechanism for all Ultra DMA transfers. Using this technology, data is registed both on the rising and falling edges of the data strobe, halving the required strobe frequency. Thus the bandwidth is:

25 MHz strobe
x 2 for double data rate clocking
x 16 bit per edge
/ 8 bits per byte
——————————–
=100 Mbytes/sec

ESD:electrostatic discharge
Shipping package, ESD protecting bag are responsibility for the users.

Controll electionics:
The driver is electronically controlled by a microprocessor, several logic modules, digital/analog modules, and various drivers and receivers. The controll electronics preforms the following major function:
1. Controls and interpres all interface signals between the host controller and driver.
2. Controls read write accessing of the disk media, including defect management and error recovery.
3. Controls staring, stopping and monitoring of the spindle.
4. Conducts a power-up sequence and calibrates the serio.
5. Analyze servo signals to provide closed loop control. These include position erre signal and estimated velocity.
6. Monitors the actuator position and determines the target track for a seek operation
7. Controls the voice coil driver to align the actuator in a desired position
8. Constantly monitors error conditions of the servo and takes corresponding action if an error occurs
9. Monitors various timers such as head settle and servo failure.
10.Perform self-checkout(diagnostics)

Actuator: The read/write heads are mounted in the actuator. The actuator is a swing-arm assembly driven by a voice coild motor. A closed-loop positioning servo controls the environment of the actuator. An embedded servo patterm supplied feedback to the positioning servo to keep the read/write heads centered over the desired track.

The actuator assembly is balanced to allow vertical or horizontal mounting without adjustment. When the driver is powered off, the actuator automatically moves the head to the actuator ramp outside of the disk where it parks.

Key: Pin position 20 has no connection pin, it is recommended to close the respective position of the cable connector in order to avoid incorrect insertion.

NDS8.0 does not support posixAccount,shadowAccount,samba schema default. I add these attributes and objectclass manually by ConsoleOne.

Before import posixAccount and shadowAccount, run ConsoleOne, “LDAP Group-Attribute Mapping”, remove the “unique ID” and “GID” firstly. This step must not be ignored.

Then import “attribute ldif”, “objectclassed ldif” and “samba.nds” in order. Restart ConsoleOne to make it activated. Through path “User-Extensions of this object”, I could add these attribute or objectclass to identied user.

attribute.ldif(posixAccount,shadowAccount,Account)
————————————————–
# Attributes for RFC2307:posixAccount
dn: cn=schema
changetype: modify
add: attributetypes
attributeTypes: ( 1.3.6.1.1.1.1.0 NAME ‘uidNumber’ DESC ‘uidNumber’ SYNTAX 1.3.6.1.4.1.1466.115.121.1.27 SINGLE-VALUE)

dn: cn=schema
changetype: modify
add: attributetypes
attributeTypes: ( 1.3.6.1.1.1.1.4 NAME ‘loginShell’ DESC ‘loginShell’ SYNTAX 1.3.6.1.4.1.1466.115.121.1.15 SINGLE-VALUE)

dn: cn=schema
changetype: modify
add: attributetypes
attributeTypes: ( 1.3.6.1.1.1.1.1 NAME ‘gidNumber’ DESC ‘gidNumber’ SYNTAX 1.3.6.1.4.1.1466.115.121.1.27 SINGLE-VALUE)

dn: cn=schema
changetype: modify
add: attributetypes
attributeTypes: ( 1.3.6.1.1.1.1.2 NAME ‘gecos’ DESC ‘gecos’ SYNTAX 1.3.6.1.4.1.1466.115.121.1.15 SINGLE-VALUE)

dn: cn=schema
changetype: modify
add: attributetypes
attributeTypes: ( 1.3.6.1.1.1.1.3 NAME ‘homeDirectory’ DESC ‘homeDirectory’ SYNTAX 1.3.6.1.4.1.1466.115.121.1.26 SINGLE-VALUE)

# Attributes for shadowAccount
dn: cn=schema
changetype: modify
add: attributetypes
attributeTypes: ( 1.3.6.1.1.1.1.11 NAME ‘shadowFlag’ DESC ‘shadowFlag’ SYNTAX 1.3.6.1.4.1.1466.115.121.1.27 SINGLE-VALUE)

dn: cn=schema
changetype: modify
add: attributetypes
attributeTypes: ( 1.3.6.1.1.1.1.5 NAME ‘shadowLastChange’ DESC ‘shadowLastChange’ SYNTAX 1.3.6.1.4.1.1466.115.121.1.27 SINGLE-VALUE)

dn: cn=schema
changetype: modify
add: attributetypes
attributeTypes: ( 1.3.6.1.1.1.1.10 NAME ‘shadowExpire’ DESC ‘shadowExpire’ SYNTAX 1.3.6.1.4.1.1466.115.121.1.27 SINGLE-VALUE)

dn: cn=schema
changetype: modify
add: attributetypes
attributeTypes: ( 1.3.6.1.1.1.1.9 NAME ‘shadowInactive’ DESC ‘shadowInactive’ SYNTAX 1.3.6.1.4.1.1466.115.121.1.27 SINGLE-VALUE)

dn: cn=schema
changetype: modify
add: attributetypes
attributeTypes: ( 1.3.6.1.1.1.1.8 NAME ‘shadowWarning’ DESC ‘shadowWarning’ SYNTAX 1.3.6.1.4.1.1466.115.121.1.27 SINGLE-VALUE)

dn: cn=schema
changetype: modify
add: attributetypes
attributeTypes: ( 1.3.6.1.1.1.1.7 NAME ‘shadowMax’ DESC ‘shadowMax’ SYNTAX 1.3.6.1.4.1.1466.115.121.1.27 SINGLE-VALUE)

dn: cn=schema
changetype: modify
add: attributetypes
attributeTypes: ( 1.3.6.1.1.1.1.6 NAME ‘shadowMin’ DESC ‘shadowMin’ SYNTAX 1.3.6.1.4.1.1466.115.121.1.27 SINGLE-VALUE)

# Attributes for RFC1274:Account
dn: cn=schema
changetype: modify
add: attributetypes
attributeTypes: ( 0.9.2342.19200300.100.1.9 NAME ‘host’ DESC ‘host’ SYNTAX 1.3.6.1.4.1.1466.115.121.1.15)

objectclass.ldif(posixAccount,shadowAccount,Account)
—————————————————–
# Attrbutes for RFC 2307
dn: cn=schema
changetype: modify
add: objectclasses
objectClasses: (0.9.2342.19200300.100.4.5 NAME ‘account’ DESC ‘account’ AUXILIARY MAY host)

dn: cn=schema
changetype: modify
add: objectClasses
objectClasses: (1.3.6.1.1.1.2.0 NAME ‘posixAccount’ DESC ‘posixAccount’ AUXILIARY MAY (uidNumber $ loginShell $ gecos $ gidNumber $ homeDirectory ))

dn: cn=schema
changetype: modify
add: objectClasses
objectClasses: (1.3.6.1.1.1.2.1 NAME ‘shadowAccount’ DESC ‘shadowAccount’ AUXILIARY MAY (shadowLastChange $ shadowFlag $ shadowExpire $ shadowInactive $ shadowMax $ shadowMin $ shadowWarning ))

samba-nds.schema
——————————-
/SNAZ_build/samba/example/LDAP/samba-nds.schema