The Openfiler NAS/SAN Appliance (NSA) is a Storage Management Operating System / NAS Appliance distribution. It is powered by the Linux 2.6 kernel and Open Source applications such as Apache, Samba, LVM2, ext3, Linux NFS and iSCSI Enterprise Target. Openfiler combines these ubiquitous technologies into a small, easy to manage solution fronted by a powerful web-based management interface. Openfiler allows you to build a Network Attached Storage (NAS) and/or Storage Area Network (SAN) appliance, using industry-standard hardware, in less than 10 minutes of installation time.
Building upon the popularity of server virtualization technologies such as VMware, Virtual Iron, and Xen, Openfiler can also be deployed as a virtual machine instance or on a bare metal machine.
This deployment flexibility of Openfiler ensures that storage administrators are able to make the best use of system performance and storage capacity resources when allocating and managing networked storage in a multi-platform environment.
Openfiler is ideally suited for use with High Availability Recital applications as it incorporates:
- Heartbeat cluster manager
- drbd disk replication
- CIFS
- NFS
- Software and hardware RAID
- FTP
- rsync
- HTTP/DAV
- iSCSI
- LVM2
- Multiple NIC bonding for High Availability
- Powerful web-based GUI
When the node is clicked set editable to false. Set editable to true in the double-click event handler.
// the click event handler
private function onclick_sourcetree(e:Event):void {
yourTree.editable = false;
}
// the doubleclick event handler
private function ondoubleclick_sourcetree(e:Event):void {
yourTree.editable = true;
yourTree.editedItemPosition = {columnIndex:0, rowIndex:sourceTree.selectedIndex};
}
Hdparm can be used to view or set many hardware characteristics of IDE or SATA drives including optical drives (and even some SCSI drives). For example, the read-lookahead feature can be enabled or disabled. Also of interest is that the on board write caching can be disabled. This may or may not be of use when trying to optimize the writing of data to the drive especially when the operating system and/or file system itself may also perform write caching.
Some options of hdparm are dangerous and are generally listed as such in the man page.
Hdparm is available from SourceForge and there is even a version for Windows.
Some options of hdparm are dangerous and are generally listed as such in the man page.
Hdparm is available from SourceForge and there is even a version for Windows.
Recital 10 introduced a FOREACH command, much like PHP and some other languages. This simply gives an easy way to iterate over arrays. foreach works on arrays and objects, and will issue an error when you try to use it on a variable with a different data type or an uninitialized variable. There are two syntaxes; the second is a minor but useful extension of the first:
The second form does the same thing, except that the current element's key will be assigned to the variable key on each loop. This form works only on associative arrays and objects.
FOREACH array_expression AS value
statements...
ENDFOR
FOREACH array_expression AS key => value
statements...
ENDFOR
The first form loops over the array given by array_expression. On each loop, the value of the current element is assigned to value and the internal array pointer is advanced by one (so on the next loop, you'll be looking at the next element). The second form does the same thing, except that the current element's key will be assigned to the variable key on each loop. This form works only on associative arrays and objects.
The SET RELATION Recital Navigational Data Command can be used to link two (or more) tables based on the master index key of the child table. With a relation active, as you move through the parent table, the record pointer also moves in the child table, automatically selecting the first related record or moving to the end of file if no related record exists.
The code above will display the productid from the first related record, but you will often want to display information from all the related records in the child or detail table as in an SQL Left Outer Join.
In this case, we can use a second nested DO WHILE loop, for example:
Or we can use the SET SKIP command. The SET SKIP command can be used with DISPLAY, LIST and REPORT and automatically skips through all the related records in the child table.
LIST and DISPLAY offer a number of keyword options to allow you to configure the display output. REPORT offers full column based report design.
open database southwind
// open child table
use order_details order orderid in 0
// open parent table
use orders order orderid in 0
set relation to orderid into order_details
do while not eof()
? orders.orderid, order_details.productid
skip
enddo
The code above will display the productid from the first related record, but you will often want to display information from all the related records in the child or detail table as in an SQL Left Outer Join.
open database southwind
select orders.orderid, order_details.productid;
from orders left outer join order_details;
on orders.orderid = order_details.orderid
In this case, we can use a second nested DO WHILE loop, for example:
open database southwind
use order_details order orderid in 0
use orders order orderid in 0
set relation to orderid into order_details
do while not eof()
// Display first or 0 child record
? orders.orderid, order_details.productid
// Display any additional child records
do while not eof(order_details)
? orders.orderid, order_details.productid
skip in order_details
enddo
skip
enddo
Or we can use the SET SKIP command. The SET SKIP command can be used with DISPLAY, LIST and REPORT and automatically skips through all the related records in the child table.
open database southwind
use order_details order orderid in 0
use orders order orderid in 0
set relation to orderid into order_details
set skip on
set skip to order_details
list orders.orderid, order_details.productid
LIST and DISPLAY offer a number of keyword options to allow you to configure the display output. REPORT offers full column based report design.
In Linux you can run lsof and pipe it though grep for the files you are interested in, for example;
$ lsof | grep db.exe | grep accounts db.exe 16897 john 6uw REG 253,0 20012 3413872 /usr/recital100/qa/accounts.dbf db.exe 16897 john 7u REG 253,0 4176 3413885 /usr/recital100/qa/accounts.dbxIf you want to check for locks you can use lslk, for example;
$ lslk | grep db.exe | grep accounts db.exe 16897 253,0 3413872 20012 w 0 0 0 12319 0 /usr/recital100/qa/accounts.dbfIf you don't have lslk installed you can install it with one of the updaters, for example on redhat linux:
$ yum update lslk
When debugging C code it is common to write debugging to an external text file using the __FILE__ and __LINE__ preprocessor defines to trace execution flow.
Unfortunately java does not support __FILE__ and __LINE__ but you can get the same functionality with this code which can be placed in one of your libraries.
Unfortunately java does not support __FILE__ and __LINE__ but you can get the same functionality with this code which can be placed in one of your libraries.
public static void showTrace(String msg)
{
if (msg.length() > 0) System.out.println(msg);
System.out.println("Trace: " +
"file " + new Throwable().getStackTrace()[1].getFileName() +
" class " + new Throwable().getStackTrace()[1].getClassName() +
" method " + new Throwable().getStackTrace()[1].getMethodName() +
" line " + new Throwable().getStackTrace()[1].getLineNumber());
}
RTOS()
Syntax
RTOS( [ <workarea> ] )Description
The RTOS() function returns all the fields in the current row as a string. The string will begin with the unique row identifier and then the deleted flag, followed by the data in the record. An optional workarea can be specified, otherwise the current workarea will be usedExample
use backup in 0
use accounts in 0
nrecs=reccount()
for i = 1 to nrecs
if rtos(accounts) != rtos(backup)
debug("record "+recno()+" don't match")
endif
next
Recital 10.0 introduced the COPY DATABASE <name> TO <name> command.. The full syntax is;
COPY DATABASE <name> TO <name> [ IF [ NOT ] EXISTS ]This command is used to copy an existing database to a new database. By default an error will be returned if the target database already exists. Specifying the optional IF NOT EXISTS keywords no error will be returned if the target database already exists. If the optional IF EXISTS keywords are specified and the target database already exists, then it will be removed before the copy. Both the databases must be closed before they can be copied.
In an interesting article at Linux Magazine, Sam Ockman discusses the origin of the term "Open Source". Check it out here.