Tuesday, January 13, 2009

pkg-get on solaris, there is new link for url

After not using pkg-get on Solaris for couple months, I got error like this.

bash-3.00# /opt/csw/bin/pkg-get -i nano
WARNING: gpg not found
No existing install of CSWnano found. Installing...
Trying http://ibiblio.org/pub/packages/solaris/csw/unstable/i386/5.10/nano-1.2.5,REV=2005.08.14-SunOS5.8-i386-CSW.pkg.gz
--11:26:07-- http://ibiblio.org/pub/packages/solaris/csw/unstable/i386/5.10/nano-1.2.5,REV=2005.08.14-SunOS5.8-i386-CSW.pkg.gz
=> `nano-1.2.5,REV=2005.08.14-SunOS5.8-i386-CSW.pkg.gz'
Resolving ibiblio.org... 152.46.7.80
Connecting to ibiblio.org|152.46.7.80|:80... connected.
HTTP request sent, awaiting response... 404 Not Found
11:26:08 ERROR 404: Not Found.

Error downloading http://ibiblio.org/pub/packages/solaris/csw/unstable/i386/5.10/nano-1.2.5,REV=2005.08.14-SunOS5.8-i386-CSW.pkg.gz
(Perhaps you need to update your catalog?)
nano-1.2.5,REV=2005.08.14-SunOS5.8-i386-CSW.pkg.gz: No such file or directory

Attempting to update catalog, then retry

Getting catalog...
--11:26:08-- http://ibiblio.org/pub/packages/solaris/csw/unstable/i386/5.10/catalog
=> `catalog'
Resolving ibiblio.org... 152.46.7.80
Connecting to ibiblio.org|152.46.7.80|:80... connected.
HTTP request sent, awaiting response... 404 Not Found
11:26:08 ERROR 404: Not Found.

ERROR: could not get catalog file
bash-3.00#

Hey, whats going on with .. pkg-get.
Then I go to

http://solaris.reys.net/english/2006/02/pkg-get_blastwave_how-to

looking for some information, looks everything is fine.

Then i visiting this site

http://ibiblio.org/pub/packages/solaris/opencsw/

well, look the URL was change, I am not sure since when ..

so I edit the configuration pkg-get on /opt/csw/etc/pkg-get.conf

and change the default site from

url=http://ibiblio.org/pub/packages/solaris/csw/unstable

to


url=http://ibiblio.org/pub/packages/solaris/opencsw/unstable

and everything going fine.

So I download and install package using pkg-get again.

For example installing nano editor :

bash-3.00# /opt/csw/bin/pkg-get -i nano

...
/opt/csw/share/locale/ro/LC_MESSAGES/nano.mo
/opt/csw/share/locale/ru/LC_MESSAGES/nano.mo
/opt/csw/share/locale/sr/LC_MESSAGES/nano.mo
/opt/csw/share/locale/sv/LC_MESSAGES/nano.mo
/opt/csw/share/locale/tr/LC_MESSAGES/nano.mo
/opt/csw/share/locale/uk/LC_MESSAGES/nano.mo
/opt/csw/share/man/man1/nano.1
/opt/csw/share/man/man5/nanorc.5
[ verifying class ]
## Executing postinstall script.
Updating the info dir file for CSWtexinfo
chroot: exec failed: No such file or directory

Installation of was successful.
bash-3.00#

Sunday, January 4, 2009

Upgrade ports on freebsd

I want to install postgresql 8.2 from ports, but the package was not found. So I have to upgrade the newest ports.
Here is the step for upgrade the ports on FreeBSD 7.

#portsnap fetch update
#portsnap extract
#portsnap update
#Ports tree is already up to date.
#

If only spesified package only use
#portupdgrade package-name

Monday, November 17, 2008

Definisi System Administrator dan Network Administrator

Di bawah ini difinisi System Administrator dan Network Administrator saya ambilkan dari http://en.wikipedia.org/wiki/System_administrator dan http://en.wikipedia.org/wiki/Network_administrator



A system administrator, systems administrator, or sysadmin, is a person employed to maintain and operate a computer system and/or network. System administrators may be members of an information technology department.

The duties of a system administrator are wide-ranging, and vary widely from one organization to another. Sysadmins are usually charged with installing, supporting, and maintaining servers or other computer systems, and planning for and responding to service outages and other problems. Other duties may include scripting or light programming, project management for systems-related projects, supervising or training computer operators, and being the consultant for computer problems beyond the knowledge of technical support staff. A System Administrator must demonstrate a blend of technical skills and responsibility.
Contents
[hide]

* 1 Skills
* 2 Related fields
* 3 Training
* 4 Duties of a system administrator
* 5 System Administrator Privileges
* 6 See also
* 7 References
* 8 External links
o 8.1 Certification Organizations
o 8.2 Periodicals
o 8.3 Conferences
o 8.4 Books
o 8.5 Online Resources
o 8.6 Technology Unions and related links
o 8.7 Articles

Skills

The subject matter of systems administration includes computer systems and the ways people use them in an organization. This entails a knowledge of operating systems and applications, as well as hardware and software troubleshooting, but also knowledge of the purposes for which people in the organization use the computers.

However, perhaps the most important skill to a system administrator is problem solving -- frequently under various sorts of constraints and stress. The sysadmin is on call when a computer system goes down or malfunctions, and must be able to quickly and correctly diagnose what is wrong and how best to fix it.

System administrators are not software engineers or developers. It is not usually within their duties to design or write new applications software. However, sysadmins must understand the behavior of software in order to deploy it and to troubleshoot problems, and generally know several programming languages used for scripting or automation of routine tasks.

Particularly when dealing with Internet-facing or business-critical systems, a sysadmin must have a strong grasp of computer security. This includes not merely deploying software patches, but also preventing break-ins and other security problems with preventive measures. In some organizations, computer security administration is a separate role responsible for overall security and the upkeep of firewalls and intrusion detection systems, but all sysadmins are generally responsible for the security of the systems in their keep.

Related fields

Many organizations staff other jobs related to systems administration. In a larger company, these may all be separate positions within a computer support or Information Services (IS) department. In a smaller group they may be shared by a few sysadmins, or even a single person.

* A database administrator (DBA) maintains a database system, and is responsible for the integrity of the data and the efficiency and performance of the system.
* A network administrator maintains network infrastructure such as switches and routers, and diagnoses problems with these or with the behavior of network-attached computers.
* A security administrator is a specialist in computer and network security, including the administration of security devices such as firewalls, as well as consulting on general security measures.
* A web administrator maintains web server services (such as IIS or Apache) that allow for internal or external access to web sites. Tasks include managing multiple sites, administering security, and configuring necessary components and software. Responsibilities may also include software change management.
* Technical support staff respond to individual users' difficulties with computer systems, provide instructions and sometimes training, and diagnose and solve common problems.
* A computer operator performs routine maintenance and upkeep, such as changing backup tapes or replacing failed drives in a RAID array. Such tasks usually require physical presence in the room with the computer; and while less skilled than sysadmin tasks require a similar level of trust, since the operator has access to possibly sensitive data.

In some organizations, a person may begin as a member of technical support staff or a computer operator, then gain experience on the job to be promoted to a sysadmin position.

Training

Unlike many other professions, there is no single path to becoming a system administrator. Many system administrators have a degree in a related field: computer science, information technology, computer engineering, information system management, or even a trade school program. Other schools have offshoots of their Computer Science program specifically for systems administration.

Some schools have started offering undergraduate degrees in Systems Administration. The first, RIT[1] started in 1992. Others such as Rensselaer Polytechnic Institute, Marist College, and Drexel University have more recently offered degrees in Information Technology.

As of 2008, only four U.S. universities, Rochester Institute of Technology[2], New York City College of Technology,Tufts, and Michigan Tech have graduate programs in system administration.[citation needed] In Norway, there is a special English-taught MSc program organized by Oslo University College [3] in cooperation with Oslo University, named "Masters programme in Network and System Administration." University of Amsterdam (UvA) offers a similar program[1], in cooperation with Hogeschool van Amsterdam (HvA). However, many other schools offer related graduate degrees in fields such as network systems and computer security.

One of the primary difficulties with teaching system administration as a formal university discipline, is that the industry and technology changes much faster than the typical textbook and coursework certification process. By the time a new textbook has spent years working through approvals and committees, the specific technology for which it is written may have changed significantly or is now obsolete.

In addition, because of the practical nature of systems administration and the easy availability of open-source server software, many systems administrators enter the field self-taught.

Generally, a prospective administrator will be required to have some experience with the computer system he or she is expected to manage. In some cases, candidates are expected to possess industry certifications such as the Microsoft MCSA, MCSE, Red Hat RHCE, Novell CNA, CNE, Cisco CCNA or CompTIA's A+ or Network+, Sun Certified SCNA, among others.

Sometimes, almost exclusively in smaller sites, the role of system administrator may be given to a skilled user in addition to or in replacement of his or her duties. For instance, it is not unusual for a mathematics or computing teacher to serve as the system administrator of a secondary school.

Duties of a system administrator

A system administrator's responsibilities might include:

* Analyzing system logs and identifying potential issues with computer systems.
* Introducing and integrating new technologies into existing data center environments.
* Performing routine audits of systems and software.
* Performing backups.
* Applying operating system updates, patches, and configuration changes.
* Installing and configuring new hardware and software.
* Adding, removing, or updating user account information, resetting passwords, etc.
* Answering technical queries.
* Responsibility for security.
* Responsibility for documenting the configuration of the system.
* Troubleshooting any reported problems.
* System performance tuning.
* Insuring that the network infrastructure is up and running.

In larger organizations, some tasks listed above may be divided among different system administrators or members of different organizational groups. For example, a dedicated individual(s) may apply all system upgrades, a Quality Assurance (QA) team may perform testing and validation, and one or more technical writers may be responsible for all technical documentation written for a company.

In smaller organizations, the system administrator can also perform any number of duties elsewhere associated with other fields:

* Technical support
* Database administrator (DBA)
* Network administrator/analyst/specialist
* Application analyst
* Security administrator
* Programmer

System administrators, in larger organizations, tend not to be system architects, system engineers, or system designers. However, like many roles in this field, demarcations between systems administration and other technical roles often are not well defined in smaller organizations. Even in larger organizations, senior systems administrators often have skills in these other areas as a result of their working experience.

In smaller organizations, IT/computing specialties are less often discerned in detail, and the term system administrator is used in a rather generic way — they are the people who know how the computer systems work and can respond when something fails.


Network administrator is a modern profession responsible for the maintenance of computer hardware and software that comprises a computer network. This normally includes the deployment, configuration, maintenance and monitoring of active network equipment. A related role is that of the network specialist, or network analyst, who concentrate on network design and security.


The Network Administrator is usually the highest level of technical/network staff in an organization and will rarely be involved with direct user support. The Network Administrator will concentrate on the overall health of the network, server deployment, security, ensuring network connectivity throughout a company's LAN/WAN infrastructure, and all other technical considerations at the network level of an organizations technical hierarchy. Network Administrators are considered Tier 3 support personnel that only work on break/fix issues that could not be resolved at the Tier1 (helpdesk) or Tier 2 (desktop/network technician) levels.

Depending on the company, the Network Administrator may also design and deploy networks. However, these tasks may be assigned to a Network Engineer should one be available to the company.

The actual role of the Network Administrator will vary from company to company, but will commonly include activities and tasks such as network address assignment, assignment of routing protocols and routing table configuration as well as configuration of authentication and authorization – directory services. It often includes maintenance of network facilities in individual machines, such as drivers and settings of personal computers as well as printers and such. It sometimes also includes maintenance of certain network servers: file servers, VPN gateways, intrusion detection systems, etc.

Network specialists and analysts concentrate on the network design and security, particularly troubleshooting and/or debugging network-related problems. Their work can also include the maintenance of the network's authorization infrastructure, as well as network backup systems.

The administrator is responsible for the security of the network and for assigning IP addresses to the devices connected to the networks. Assigning IP addresses gives the subnet administrator some control over the professional who connects to the subnet. It also helps to ensure that the administrator knows each system that is connected and who personally is responsible for the system.

Wednesday, October 15, 2008

Apologies - our website is struggling to cope with the unprecedented

Apologies - our website is struggling to cope with the unprecedented
demand for the new release 3.0 of OpenOffice.org. The technical teams are
trying to come up with a solution.

Thank you for your patience.
Please consider to contribute to the Project via a monetary donation
OpenOffice.org download


Wooow ... seems all people around the world waiting for open office 3.0, yeah of course me too.



Capture on 15 October 2008 9:27 PM, GMT +7, WIB

Introducing Bernoulli Integral For Solving Some Physical Problems

Some of both modeling and problems in physics have been commonly presented in a first-order nonlinear differential equations (DE) of constant coefficients. Because the DE are integrable, therefore one must have an integral formulation for solving the physical problems. This paper introduces Bernoulli integral to complete the Tables of Integral for all of the Mathematical Handbooks. Basically, the Bernoulli integral is integral form of the homogeneous Bernoulli differential equation (BDE) of
constant coefficients. Under proper transformation, the Bernoulli integral can be used to generate another integral formulation especially for integrals that can be transformed into arctangent DE. By using the Bernoulli integral, one can create its self the integral formulation of solving the physical problems, and hence reduces utilization the tables of integral. A special application in generating Euler
formula also presented.

Key-words : Arctangent, tangent, arctangent differential equation, Bernoulli equation, Bernoulli differential equation, integral, Bernoulli integral, Schrödinger equation, modulation instability, Euler formula, Argand diagram, electromagnetic, logistic growth, chaotic, soliton, fluxon, squeezed laser

I. INTRODUCTION
Some of both modeling and problems in physics have been commonly presented in a first-order nonlinear differential equations (DE) of constant coefficients For instance, in designing electromagnetic apparatus [Markus,1979], the logistic growth process [Welner,2004], chaotic behavior [Barger et al,1995], the generation and propagation of soliton [Wu et al 2005],[Morales,2005], the transport of fluxon [Gonzile et al,2006], the generation of squeezed laser [Friberg,1996 ],etc. One requires Table of Integral to solve a specific integral for solving such differential equation [Spiegel,MR,1968]. To complete the Table of integral,
we introduce Bernoulli integral that until now not including in both of the Table integral and mathematical Handbook. By using the Bernoulli integral, one can create the integral formulation required in solving the physical problems, and hence reduces utilization the Tables of integral.


Full version of this article please visit and download the article.
http://rohedi.com/content/view/34/1/

Thursday, September 18, 2008

Delete all except one

How to delete all file except file(s) ...

> ls
1 2 3 4 5 6 7
>

I want to delete files 3, 4, 5, 6, 7 except 1 & 2
> rm `ls * | egrep -v "1|2"`
> ls
1 2
>

Tuesday, September 2, 2008

Backup and Restore Alfresco

Overview

Backing up an Alfresco repository involves backing up both the directory pointed to by the dir.root setting AND the database Alfresco is configured to use, as if they were a single unit. Backing up either one without the other results in a backup that cannot be successfully restored.

Similarly, when you restore an Alfresco backup you must restore both the dir.root directory AND the Alfresco database from the same backup set - restoring either one in isolation is guaranteed to corrupt your repository.

The dir.root directory is usually defined in /alfresco/extension/custom-repository.properties. By default this directory is named 'alf_data' and is located within the directory where Alfresco is installed.
[edit] Cold Backup Procedure

By default, the dir.root contains both the content and indexes, so for cold backup it is possible to backup just the content and then do a full reindex when a backup is restored. A full reindex can be a time consuming process however, so the steps below include the indexes in the backup.

1. Stop Alfresco
2. Backup the database Alfresco is configured to use, using your database vendor's backup tools
3. In parallel, backup the Alfresco dir.root directory in its entirety
4. Store both the database and Alfresco dir.root backups together as a single unit (neither is useful without the other)
5. Start Alfresco

[edit] Hot Backup Procedure
[edit] Overview

1. Backup the database Alfresco is configured to use, using your database vendor's backup tools (see below for details)
2. As soon as the database backup completes, backup specific subdirectories in the Alfresco dir.root (see below for details)
3. Store both the database and Alfresco dir.root backups together as a single unit (neither is useful without the other)

[edit] Backing up the Database

In an Alfresco system, the ability to support hot backup is fundamentally dependent on the hot backup capabilities of the database product Alfresco is configured to use. Specifically, it requires a tool that can "snapshot" a consistent version of the Alfresco database (ie. it must capture a transactionally consistent copy of all of the tables in the Alfresco database). In addition, to avoid serious performance problems in the running Alfresco system, this "snapshot" operation should operate without taking out locks in the Alfresco database.

Backup capabilities vary widely between relational database products, and you should ensure that any backup procedures that are instituted are validated by a qualified, experienced Database Administrator before being put into a production environment.
[edit] Backing up the Filesystem

Backup the following subdirectories of the Alfresco dir.root directory using whatever tools you're comfortable with (rsync, xcopy, etc.):

* contentstore
* contentstore.deleted
* audit.contentstore
* backup_lucene_index

IMPORTANT NOTE: Never, never, under any circumstances, attempt to backup the lucene-indexes subdirectory while Alfresco is running. Doing so is almost certain to cause Lucene index corruption.
[edit] Notes

* Alfresco includes a background job responsible for backing up the Lucene indexes that (by default) is configured to run at 3am each night. The hot backup process must not run concurrently with this background job, so you should either ensure that the hot backup completes by 3am, or wait until the index backup job has completed before initiating a hot backup.
* The Alfresco WCM functionality includes a background job called the 'avmOrphanReaperJob' that must not be allowed to run while a hot backup is in progress. By default this job is scheduled to run every minute, but this can be reconfigured by overriding the default schedule defined in scheduled-jobs-context.xml. Please make sure you are familiar with Alfresco's Repository Configuration mechanism before making any configuration changes. If you are not using the Alfresco WCM functionality no action is required.

[edit] Restore Procedure

1. Stop Alfresco
2. Copy the existing dir.root to temp location
3. Restore dir.root
4. If you're restoring from a hot backup, rename dir.root/backup_lucene_index to dir.root/lucene-indexes
5. Restore the database from the database backups
6. Start Alfresco

[edit] Lucene Index Restoration

Note that in addition to full restorations, the backup sets created via either the cold or hot backup procedures described above can also be used to restore just the Lucene indexes. This is useful in cases where the repository itself does not need to be restored but for some reason the Lucene indexes are stale.

The Lucene index restoration process is as follows:

1. Stop Alfresco
2. Move the existing dir.root/lucene-indexes directory out of the way
3. If you're performing cold backups, restore dir.root/lucene-indexes from the most recent backup step
4. If you're performing hot backups, restore dir.root/backup_lucene_index from the most recent backup step and rename it to dir.root/lucene-indexes
5. Restart Alfresco

Upon restarting, Alfresco will (by default) detect that the indexes are stale, and incrementally reindex just that content that has changed since the last backup was performed. As the size of your content set grows, the time savings from performing incremental reindexing rather than full reindexing will become greater and greater (incremental reindexing is typically measured in minutes, whereas full reindexing can take hours for large content sets).

Important note: in order for incremental reindexing to occur properly, you should leave the index.recovery.mode property at its default value of "VALIDATE". Setting this property to "FULL" forces a full reindex even if incremental reindexing is possible (thereby negating any benefits from this procedure).

----
Copy Paste From http://wiki.alfresco.com/wiki/Backup_and_Restore without permission.

Sunday, August 17, 2008

Kunci Sains Dan Teknologi Ada Di Angka Kelahiran Republik Indonesia

Kunci Sains Dan Teknologi Ada Di Angka Kelahiran Republik Indonesia
Oleh : Ali Yunus Rohedi(1)
Staf Pengajar Pada Jurusan Fisika FMIPA – ITS, Surabaya
Telp/Fax : (031)5943351, e-mail : rohedi@physics.its.ac.id
(1)Kepala ROHEDI Laboratory Surabaya, e-mail : aliyunus@rohedi.com
Para visitor tentu ingat bahwa saat saya meluncurkan website rohedi.com kepada
khalayak, artikel pertama yang saya tampilkan adalah info tentang formula analitik untuk
polinomial orde positif sembarang versi saya. Pada artikel tersebut saya contohkan komparasi
nilai sisa polinomial (remainder) antara rohedi’s formula dengan hasil hitungan perangkat
lunak Matlab untuk polinomial orde 1060. Remainder hitungan rohedi’s formula tetap
konsisten dengan teori matematika yakni mendekati nol, sedangkan remainder hitungan
Matlab sangat payah karena nilainya mendekati takberhingga. Walaupun demikian saya tidak
terburu-buru mengklaim formula analitik yang saya miliki tersebut sebagai penemuan, karena
disamping paper tentang formula digdaya itu belum saya publikasikan ke manca negara, juga
karena saya masih ingin berbagi tips dengan sesama anak bangsa, siapa tahu ada diantara
visitor yang brillian mendapatkannya, sehingga saya turut berbangga mengantarkan sang
penemu meraih field medal yaitu gelar prestisius di bidang matamatika. Tak ayal lagi kelak
Indonesia akan menjadi sentra New Science sebagaimana saya ilustrasikan pada
rohedi.blogspot. Mengapa? karena tentu semua visitor akan sependapat dengan saya, bahwa
karya Profesor PTN dan PTS produk DIKTI Indonesia tentu jauh lebih hebat dari karya
ROHEDI yang hanya tamatan S2 dalam negeri.
Sebagaimana inspirasi untuk mendapatkan rohedi’s reversion sebagai teknik reversi
baru dalam menyelesaikan persamaan diferensial biasa nonlinear dalam bentuk Maclaurin
series (silahkan baca kembali artikel How to upgrade the running time of computer), untuk
mendapatkan formula analitik polinomial orde sembarang dimaksud, sayapun terinspirasi
akan ketajaman hati nurani para Pendiri Bangsa dalam menetapkan kelahiran RI (Republik
Indonesia) tercinta ini pada 17–8–1945. Pada penyelesaian persamaan diferensial arctanget,
ternyata angka-angka tanggal, bulan, dan tahun kelahiran RI tersebut termaktub dalam
koefisien deret tangent function pada suku ke 8 (delapan).

Artikel lengkap bisa di lihat di link di bawah ini.
http://rohedi.com/content/view/29/1/

Friday, August 15, 2008

snmpd problems occur when running portsentry

The problems is when installing portsentry, then running the snmpd. Because the snmp was block by portsentry. The solutions is start snmpd first, then portsentry.

Here is the sockstat from our gateway.
First, we check using sockstat to list open ports. From first line, seems port 161 "used" by portsentry. My college down the portsentry and run the snmpd. You can see in the 3rd command.

gw1# sockstat | grep 161
root portsentry 1066 4 udp4 *:161 *:*
squid squid 1016 161tcp4 127.0.0.1:3128 10.0.16.174:2642
squid squid 1016 174tcp4 117.102.83.187:53898 195.161.119.84:80
squid squid 1016 213tcp4 10.0.17.247:3128 10.0.16.161:2137
squid squid 1016 697tcp4 117.102.83.187:* 212.96.161.229:80
gw1#
gw1# netstat -a |grep snmp
udp4 0 0 *.snmptrap *.*
udp4 0 0 *.snmp *.*
gw1# sockstat | grep 161
root snmpd 60836 10 udp4 *:161 *:*
squid squid 1016 95 tcp4 10.0.17.247:3128 10.0.16.161:2242
squid squid 1016 161tcp4 127.0.0.1:3128 10.0.16.174:2642
squid squid 1016 174tcp4 117.102.83.187:53898 195.161.119.84:80
squid squid 1016 209tcp4 10.0.17.247:3128 10.0.16.49:2161
gw1#

Saturday, July 26, 2008

Tentang Bayam

Tentang BAYAM



Kalau memasak makanan yang mengandung bayam, cukup buat satu porsi aja ya. Intinya, jangan pernah memanasi makanan yang mengandung bayam. Loh, kenapa? Ada beberapa alasan. Ini dia :



a. Bayam mengandung zat besi yang berupa Fe2+ (ferro)

Kalau dia terlalu lama kontak dengan O2 (oksigen dari udara), Fe2+ akan teroksidasi menjadi Fe3+ (ferri). Meski sama-sama zat besi, yang berguna bagi kita adalah ferro. Sedangkan ferri bersifat toxid pada bayam. Jadi kalau bayam dipanasi, akan berlaku oksidasi tersebut.



b. Jangan pernah mengonsumsi bayam lebih dari 5 jam

Soalnya, selain mengandung zat yg disebutin tadi itu, bayam juga mengandung zat Nitrat (NO3). Kalau teroksidasi oleh udara, maka akan menjadi NO2 (nitrit). Nitrit adalah senyawa yang tidak berwarna, tidak berbau, dan bersifat racun bagi tubuh manusia.



Menurut John S Wishnok, bayam segar yang baru dicabut dari persemaiannya telah mengandung senyawa nitrit kira-kira sebanyak 5 mg/kg. Bila bayam disimpan di lemari es selama 2 minggu, kadar nitrit akan meningkat sampai 300 mg/kg. Dengan kata lain, dalam 1 hari penyimpanan, senyawa nitrit akan meningkat 21 mg/kg (7%).

Efek toksik (meracuni tubuh) yang ditimbulkan oleh Nitrit bermula dari reaksi oksidasi Nitrit dengan zat besi dalam sel darah merah, tepatnya di dalam Hemoglobin (Hb).

Telah kita ketahui bahwa salah satu tugas hemoglobin adalah mengikat oksigen untuk disalurkan ke seluruh organ tubuh. Ikatan nitrit dengan hemoglobin,disebut Methemoglobin, mengakibatkan hemoglobin tidak mampu mengikat oksigen. Jika jumlah methemoglobin mencapai lebih dari 15% dari total hemoglobin, maka akan terjadi keadaan yang disebut Sianosis, yaitu suatu keadaan dimana seluruh jaringan tubuh manusia kekurangan oksigen. Jika hal ini terjadi pada bayi dikenal dengan nama "Blue Baby".

Efek toksik lainnya adalah kemampuan nitrit bereaksi dengan Amino sekunder dapat membentuk senyawa yang dapat menyebabkan kanker.



c. Jangan masak bayam pake panci alumunium

Soalnya bisa bereaksi dengan zat besi yang ada di bayam, dan... jadi racun.



Tips mengkonsumsi bayam :

* Pilih bayam yang baru dipetik dan masih segar

* Hendaknya langsung diolah setelah mendapatkan bayam segar

* Jangan terlalu lama disimpan dalam lemari es.



Jadi takut mengonsumsi bayam?? JANGAN ... soalnya, kandungan nutrisinya sangat TOP BANGET. Bahkan, bayam disebut sebagai King of Vegetables.

Sumber: Searching google, dan dapat di bawah ini.
http://www.mail-archive.com/milis-nova@news.gramedia-majalah.com/msg01308.html