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A good article describing the configuration of samba for file/record locking can be found here.

Basically you must add these directives to the smb.conf file:

[data] 
oplocks = False 
level2 oplocks = False

The default oplock type is Level1. Level2 oplocks are enabled on a per-share basis in the smb.conf file. Alternately, you could disable oplocks on a per-file basis within the share: 

veto oplock files = /*.dbf/*.DBF/*.ndx/*.NDX/*.dbx/*.DBX/*.dbt/*.DBT/

You can further tune samba by following this guide.

If you specify the Common Internet File System (CIFS) when you mount the samba share then you must specify the following options
mount -t cifs {mount-point} -o username=name,pass=pass,directio
The directio option is used to not do inode data caching on files opened on this mount. This precludes mmaping files on this mount. In some cases with fast networks and little or no caching benefits on the client (e.g. when the application is doing large sequential reads bigger than page size without rereading the same data) this can provide better performance than the default behavior which caches reads (readahead) and writes (writebehind) through the local Linux client pagecache if oplock (caching token) is granted and held. Note that direct allows write operations larger than page size to be sent to the server.

If you get the following error when trying to mount the {mount-point}
Apr 22 16:57:39 bailey kernel: Status code returned 0xc000006d NT_STATUS_LOGON_FAILURE
Apr 22 16:57:39 bailey kernel:  CIFS VFS: Send error in SessSetup = -13
Apr 22 16:57:39 bailey kernel:  CIFS VFS: cifs_mount failed w/return code = -13
The you need to create the Samba user specified on the mount command
smbpasswd -a username
FYI - Make sure you umount all the Samba {mount-point(s)} before shutting down Samba.
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Recital 10 enhances the APPEND FROM command. The enhancement added the following syntax ;
APPEND FROM  TYPE CSV <file-name.csv> 
The TYPE keyword has now been enhanced to support a comma separated values (CSV) format
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The ShellEd plugin is a good shell editor for Eclipse
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For Recital to run correctly on 64bit Linux you require the ia32 shared libraries.

The 64bit port of Recital requires these libraries to allow access to 32bit Xbase and C-ISAM data files which are 32bit.

If you do not have these libraries installed you will either get a "can't find db.exe" or an "error loading shared libraries" when trying to run or license Recital.

Installing the ia32 shared libraries

Redhat EL 5 / Centos 5 / Fedora 10

  1. Insert the Red Hat Enterprise Linux 5 Supplementary CD, which contains the ia32el package.

  2. After the system has mounted the CD, change to the directory containing the Supplementary packages. For example:

    cd /media/cdrom/Supplementary/

  3. Install the ia32el package:

    rpm -Uvh ia32el-<version>.ia64.rpm

Alternatively: Note you must have the required repo's enabled.
 yum install ia32el

Ubuntu / Debian

sudo apt-get install ia32-libs

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TIP
The Compatibility Dialog settings are written to the compat.db file in <path>/conf - please ensure that the user setting the compatibility settings has write access to this file and directory.  Once these settings are written, the dialog will not be displayed unless SET COMPATIBLE is issued.

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By default Recital uses PAM to authenticate users.  It is also possible to tell PAM to use Kerberos.  Simply replace the existing entries in the /etc/pam.d/recital file with the ones below:

auth       sufficient   pam_krb5.so try_first_pass
auth       sufficient   pam_unix.so shadow nullok try_first_pass
account    required     pam_unix.so broken_shadow
account    [default=bad success=ok user_unknown=ignore] pam_krb5.so
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VMware products, such as ESX, Workstation, Server, and Fusion, come with a built-in VNC server to access guests.

This allows you to connect to the guest without having a VNC server installed in the guest - useful if a server doesn't exist for the guest or if you need access some time when a server would not work (say during the boot process). It's also good in conjunction with Headless Mode.

The VNC server is set up on a per-VM basis, and is disabled by default. To enable it, add the following lines to the .vmx:

RemoteDisplay.vnc.enabled = "TRUE" 
RemoteDisplay.vnc.port = "5901"

You can set a password with RemoteDisplay.vnc.key; details for how to calculate the obfuscated value given a plaintext password are in Compute hashed password for use with RemoteDisplay.vnc.key.

If you want more than one VM set up in this manner, make sure they have unique port numbers. To connect, use a VNC client pointing at host-ip-address:port. If you connect from a different computer, you may have to open a hole in the OS X firewall. If you use Leopard's Screen Sharing.app on the same computer as Fusion, don't use port 5900 since Screen Sharing refuses to connect to that.

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This article discusses Recital database security: from operating system file permissions through file and field protection to DES3 encryption.

Overview

A company's data is extremely valuable and must be protected, both in operation and in physical file format. Recital products provide a range of ways to protect your data.

Operating System File Permissions

The most basic level of database security is provided by the operating system. Recital database tables and indexes are individual files with their own respective operating system file permissions. Read permission is required to open a table and write permission to update a table. If a user does not have read permission they are denied access. Without write permission, a table will be opened read-only.

Here the owner, root, and members of the recital group have write permission, so can update the example table unless additional protection applies. Other users can only open the example table read-only.

# ls -l example*
-rwxrwxr-x    1 root     recital       147 Nov 29 14:27 example.dbd
-rwxrwxr-x    1 root     recital     41580 Nov 29 14:27 example.dbf
-rwxrwxr-x    1 root     recital     13312 Nov 29 14:28 example.dbt
-rwxrwxr-x    1 root     recital     19456 Nov 29 14:28 example.dbx

Note: As in the example above, a table's associated files should have the same permissions as the table itself:

File Extension

File Type

.dbd

Dictionary

.dbf

Table

.dbt

Memo

.dbx

Index


Database Dictionary

Each Recital table may have a Database Dictionary. The Dictionary can be used both to protect the integrity of the data and to protect access to the data. This section covers Column Constraints, Triggers, Security and Protection.

Column Constraints: Data Integrity

The Dictionary attributes or constraints either prevent the entry of incorrect data, e.g. must_enter and validation or aid the entry of correct data, e.g. default, picture and choicelist. The Dictionary can be modified in the character mode CREATE/MODIFY STRUCTURE worksurface, via SQL statements, or in the Recital Enterprise Studio Database Administrator.


Click image to display full size

Fig 1: MODIFY STRUCTURE Worksurface: Dictionary.

The SQL Column Constraints are as follows:

Constraint

Description

AUTO_INCREMENT | AUTOINC

Used to auto increment the value of a column.

CALCULATED

Used to calculate the value of a column.

CHECK | SET CHECK

Used to validate a change to the value of a column.

DEFAULT

Used to set a default value for the specified column.

DESCRIPTION

Used set the column description for the specified column.

ERROR

Used to define an error message to be displayed when a validation check fails.

FOREIGN KEY

Used to define a column as a Foreign Key for a parent table.

NOCPTRANS

Used to prevent code page translation for character and memo fields.

NOT NULL | NULL

Used to disallow/allow NULL values.

PRIMARY KEY

Used to define a table’s Primary Key.

RANGE

Used to specify minimum and maximum values for a date or numerical column.

RECALCULATE

Used to force recalculation of calculated columns when a column’s value changes.

REFERENCES

Used to create a relationship to an index key of another table.

UNIQUE

Used to define the column as a candidate index for the table


These can be specified in CREATE TABLE or ALTER TABLE statements:

exec sql
  OPEN DATABASE southwind;
exec sql
  ALTER TABLE customers ADD COLUMN timeref char(8) CHECK validtime(timeref)
  ERROR "Not a valid time string";

Click image to display full size

Fig 2: Database Administrator: Column Constraints and Attributes.

TRIGGERS

Table Level Triggers are event-driven procedures called before an I/O operation. These can be used to introduce another layer of checks before a particular operation is permitted to take place or to simply set up logging of those operations.

The CREATE/MODIFY STRUCTURE worksurface <TRIGGERS> menu bar option allows you to specify table level triggers. You may edit a trigger procedure from within the <TRIGGERS> menu by placing the cursor next to the procedure name and pressing the [HELP] key. A text window pops up for editing. If the table triggers are stored in separate <.prg> files, rather than in a procedure library, procedures need not be predefined (SET PROCEDURE) before using the table.


Click image to display full size

Fig 3: MODIFY STRUCTURE Worksurface: Triggers.

 

The following triggers can be selected and associated with a specified procedure name in the <TRIGGERS> menu.

Trigger

Description

UPDATE

The specified procedure is called prior to an update operation on the table. If the procedure returns .F., then the UPDATE is canceled.

DELETE

The specified procedure is called prior to a delete operation on the table. If the procedure returns .F., then the DELETE is canceled.

APPEND

The specified procedure is called prior to an append operation on the table. If the procedure returns .F., then the APPEND is canceled.

OPEN

The specified procedure is called after an open operation on the table.

CLOSE

The specified procedure is called prior to a close operation on the table.

ROLLBACK

The specified procedure is called when a user presses the [ABANDON] key in a forms based operation.


The Recital Enterprise Studio Database Administrator also allows you to associate existing programs as Table Trigger Procedures.

Click image to display full size

Fig 4: Database Administrator: Triggers.

 

Programmatically, Trigger Procedures can also be associated with a table using SQL. The following table constraints may be applied in the SQL CREATE TABLE and ALTER TABLE statements:

Trigger

Description

ONUPDATE

The specified procedure is called prior to an update operation on the table. If the procedure returns .F., then the UPDATE is canceled.
e.g. SQL> ALTER TABLE customer modify ONUPDATE "p_update";

ONDELETE

The specified procedure is called prior to a delete operation on the table. If the procedure returns .F., then the DELETE is canceled.
e.g. SQL> ALTER TABLE customer modify ONDELETE "p_delete";

ONINSERT

The specified procedure is called prior to an insert operation on the table. If the procedure returns .F., then the INSERT is canceled.
e.g. SQL> ALTER TABLE customer modify ONINSERT "p_insert";

ONOPEN

The specified procedure is called after an open operation on the table.
e.g. SQL> ALTER TABLE customer modify ONOPEN "p_open";

ONCLOSE

The specified procedure is called prior to a close operation on the table.
e.g. SQL> ALTER TABLE customer modify ONCLOSE "p_close";

ONROLLBACK

The specified procedure is called when a user presses the [ABANDON] key in a forms based operation.
e.g. SQL> ALTER TABLE customer modify ONROLLBACK "p_rollback";


SECURITY

As mentioned above, all Recital files are subject to Operating System read and write permissions. These permissions can be further refined, while still using the Operating System user and group IDs, in the Security and Protection sections of the Dictionary. The Security section handles table based operations and the Protection section focuses on individual fields.

Security and Protection rules can be defined in the CREATE/MODIFY STRUCTURE worksurface of Recital Terminal Developer, via the SQL GRANT and REVOKE statements or in the Recital Enterprise Studio Database Administrator.

Click image to display full size

Fig 5: MODIFY STRUCTURE Worksurface: Security.

 

The Security section has table operations for which Access Control Strings can be specified. An Access Control String (ACS) is a range of valid user identification codes, and is used to restrict table operations to certain individuals or groups. Each user on the system is allocated a group number and a user number. The user identification code is the combination of group and user numbers. When constructing an Access Control String of linked user identification codes, wild card characters may be used.

Example ACS

Description

[1,2]

In group 1, user 2

[100,*]

In group 100, all users

[2-7,*]

In groups 2-7, all users

[*,100-200]

In all groups, users 100-200

[1,*]&[2-7,1-7]

In group 1, all users, in groups 2-7, users 1-7


Please note that the maximum ACS length is 254 characters. OpenVMS group and user numbers are stored and specified in octal. On other Operating Systems, group and user numbers are stored and specified in decimal.

Access Control Strings may be associated with the following operations:

Operation

Description

READONLY

Users specified in the ACS have read-only access to the table. All other users have update access.

UPDATE

Users specified in the ACS have update access to the table. All other users are restricted to read-only access.

APPEND

Users specified in the ACS can append records into the table. No other users can append.

DELETE

Users specified in the ACS can delete records from the table. No other users can delete.

COPY

Users specified in the ACS can copy records from the table. No other users can copy.

ADMIN

Users specified in the ACS can use the following commands:
SET DICTIONARY TO
MODIFY STRUCTURE
PACK
ZAP
REINDEX
All other users cannot, except the creator of the table, who is always granted ADMIN access.


The corresponding SQL privileges are:

Operation

Description

SELECT

Users specified in the ACS may name any column in a SELECT statement. All other users have update access.

UPDATE

Users specified in the ACS may name any column in an UPDATE statement. All other users are restricted to read-only access.

INSERT

Users specified in the ACS can INSERT rows into the table. No other users can INSERT.

DELETE

Users specified in the ACS can DELETE rows from the table. No other users can DELETE.

ALTER

Users specified in the ACS can use the ALTER TABLE statement on this table.

READONLY

Users specified in the ACS may read any column in a SELECT statement. All other users have update access.


// Grant insert privilege for the customer table
exec sql
  OPEN DATABASE southwind;
exec sql
  GRANT UPDATE (lastname, firstname)
  INSERT ON customers
  TO '[20,100]'; 
	
// Grant all privileges to all users
exec sql
  OPEN DATABASE southwind;
exec sql
  GRANT ALL 
  ON shippers TO PUBLIC;

PROTECTION

Security and Protection rules can be defined in the CREATE/MODIFY STRUCTURE worksurface of Recital Terminal Developer, via the SQL GRANT and REVOKE statements or in the Recital Enterprise Studio Database Administrator.

Click image to display full size

Fig 6: Database Administrator: Protection.

 


The format of the ACS is the same as in <SECURITY> above. The following protection can be defined:

Operation

Description

READONLY

Users specified in the ACS have read-only access to the field. All other users have update access.

UPDATE

Users specified in the ACS have update access to the field. All other users are restricted to read-only access.


Recital Terminal Developer also has 'HIDDEN' Protection:

Operation

Description

HIDDEN

Users specified in the ACS see the 'hiddenfield'character rather than the data in the field. All other users see the data.


Hidden fields can be accessed and viewed on a work surface, but the field contains the hiddenfield character, ‘?’. If the field is referenced in an expression, it will contain the following: blanks for character fields, ‘F’ for logical fields, 00/00/0000 for date fields and blank for memo fields.

The corresponding SQL privileges are:

Operation

Description

SELECT

Users specified in the ACS may name the column in a SELECT statement. All other users have update access.

UPDATE

Users specified in the ACS may name the column in an UPDATE statement. All other users are restricted to read-only access.

READONLY

Users specified in the ACS may read the column in a SELECT statement. All other users have update access.


// Grant update privilege for columns lastname and firstname from the customer table
exec sql
  OPEN DATABASE southwind;
exec sql
  GRANT UPDATE (lastname, firstname)
  customers TO '[20,100]';

Encryption

From Recital 8.5 onwards, Recital installations that have the additional DES3 license option have the ability to encrypt the data held in Recital database tables. Once a database table has been encrypted, the data cannot be accessed unless the correct three-part encryption key is specified, providing additional security for sensitive data.

ENCRYPT

The ENCRYPT Recital 4GL command is used to encrypt the data in the specified table or tables matching a skeleton. If the skeleton syntax is used, then all matching tables will be given the same encryption key. The encryption key is a three part comma-separated key and may optionally be enclosed in angled brackets. Each part of the key can be a maximum of 8 characters. The key is DES3 encrypted and stored in a .dkf file with the same basename as the table. After encryption, the three parts of the key must be specified correctly before the table can be accessed.

// Encrypt individual tables
encrypt customers key "key_1,key_2,key_3"
encrypt employees key "<key_1,key_2,key_3>"

// Encrypt all .dbf files in the directory
encrypt *.dbf key "key_1,key_2,key_3"
SET ENCRYPTION

If a database table is encrypted, the correct three-part encryption key must be specified before the table's data or structure can be accessed. The SET ENCRYPTION TO set command can be used to specify a default encryption key to be used whenever an encrypted table is accessed without the key being specified. The encryption key is a three part comma-separated key.

If the command to access the table includes the key, either by appending it to the table filename specification or using an explicit clause, this will take precedence over the key defined by SET ENCRYPTION TO.

Issuing SET ENCRYPTION TO without a key causes any previous setting to be cleared. The key must then be specified for each individual encrypted table.

The default key defined by SET ENCRYPTION is only active when SET ENCRYPTION is ON. SET ENCRYPTION OFF can be used to temporarily disable the default key. The SET ENCRYPTION ON | OFF setting does not change the default key itself. SET ENCRYPTION is ON by default.

// Encrypt individual tables
encrypt customers key "key_1,key_2,key_3"
encrypt shippers key "key_2,key_3,key_4"
// Specify a default encryption key
set encryption to "key_1,key_2,key_3"
// Open customers table using the default encryption key
use customers
// Specify shippers table's encryption key
use shippers<key_2,key_3,key_4>
// Disable the default encryption key
set encryption to
// Specify the individual encryption keys
use customers encryption "key_1,key_2,key_3"
use shippers<key_2,key_3,key_4>
DECRYPT

The DECRYPT command is used to decrypt the data in the specified table or tables matching a skeleton. The specified key must contain the three part comma-separated key used to previously encrypt the table and may optionally be enclosed in angled brackets. The skeleton syntax can only be used if all tables matching the skeletonhave the same key.

The DECRYPT command decrypts the data and removes the table’s .dkf file. After decryption, the key need no longer be specified to gain access to the table.

// Decrypt individual tables
decrypt customers key "key_1,key_2,key_3"
decrypt employees key "<key_1,key_2,key_3>"

// Decrypt all .dbf files in the directory
decrypt *.dbf key "key_1,key_2,key_3"

All of the following commands are affected when a table is encrypted:

  • APPEND FROM
  • COPY FILE
  • COPY STRUCTURE
  • COPY TO
  • DIR
  • USE
  • SQL INSERT
  • SQL SELECT
  • SQL UPDATE
APPEND FROM
Used to append records to the active table from another table.
// The key must be specified for an encrypted source table
use mycustomers append from customers encryption "key_1,key_2,key_3"; for country = "UK"
COPY FILE
Used to copy a file.
// The key file must also be copied for an encrypted source table
// as the target table will be encrypted
encrypt customers key "key_1,key_2,key_3" copy file customers.dbf to newcustomers.dbf copy file customers.dkf to newcustomers.dkf use newcustomers encryption "key_1,key_2,key_3"
COPY STRUCTURE
Used to copy a table's structure to a new table.
// The key file is automatically copied for an encrypted source table
// and the target table encrypted
encrypt customers key "key_1,key_2,key_3"
use customers encryption "key_1,key_2,key_3" copy structure to blankcust use blankcust encryption "key_1,key_2,key_3"
COPY TO
Used to copy a table.
// By default, the key file is automatically copied for an encrypted
// source table and the target table encrypted with the same key
encrypt customers key "key_1,key_2,key_3"
use customers encryption "key_1,key_2,key_3"
copy to newcustomers
use newcustomers encryption "key_1,key_2,key_3"

// You can also create a copy with a different key
encrypt customers key "key_1,key_2,key_3"
use customers encryption "key_1,key_2,key_3"
copy to newcustomers encrypt "newkey_1,newkey_2,newkey_3"
use newcustomers encryption "newkey_1,newkey_2,newkey_3"

// Or create a decrypted copy
encrypt customers key "key_1,key_2,key_3"
use customers encryption "key_1,key_2,key_3"
copy to newcustomers decrypt
use newcustomers

// You can also create an encrypted copy of a non-encrypted source table
use orders
copy to encorders encrypt "newkey_1,newkey_2,newkey_3"
use encorders encryption "newkey_1,newkey_2,newkey_3"
DIR
Used to display a directory listing of tables.
// Encrypted tables are flagged as such with (DES3)
> open database southwind
> dir
Current database: southwind
Tables				# Records		Last Update	Size		Dictionary	Triggers	Security
categories.dbf			8			01/10/06		24576	None		None		None
cisamdemo.dbf       ---> CISAM/Bridge        [cisamdemo]
customers.dbf (DES3)		91			05/12/04		49600	None		None		None
employees.dbf			9			05/12/04		25520	None		None		None
example.dbf   (DES3)		100			12/24/05		38080	Yes		Yes		None
order_details.dbf			2155			05/12/04		296320	None		None		None
orders.dbf				829			05/12/04		232704	None		None		None
products.dbf			77			05/12/04		37112	None		None		None
productsbyname.dbf		77			05/12/04		29104	None		None		None
shippers.dbf  (DES3)		3			05/12/04		20864	None		None		None
suppliers.dbf			29			12/08/05		29992	Yes		None		None

   0.765 MB in 11 files.
   1.093 GB remaining on drive.
USE
Used to open a table.
// The three part key must be specified to open an
// encrypted table.  All of the following are valid.
// 1. Specifying a default encryption key before opening the table
set encryption to "key_1,key_2,key_3"
use customers
// 2. Appending the key to the filename
use customers<key_1,key_2,key_3>
// 3. Using the ENCRYPTION clause, optionally specifying angled brackets
use customers encryption "key_1,key_2,key_3"
use customers encryption "<key_1,key_2,key_3>"
SQL INSERT
Used to add a row to a table via SQL.
// The three part key can be specified using a
// default encryption key before opening the table
exec sql
  OPEN DATABASE southwind;
exec sql
  SET ENCRYPTION TO "key_1,key_2,key_3";
exec sql
  INSERT INTO customers
  (customerid, companyname)
  VALUES
  ('RECIT','Recital Corporation');
// Or by appending the key to the filename
exec sql
  OPEN DATABASE southwind;
exec sql
  INSERT INTO customers<key_1,key_2,key_3>
  (customerid, companyname)
  VALUES
  ('RECIT','Recital Corporation');
SQL SELECT
Used to return data from a table via SQL.
// The three part key can be specified using a
// default encryption key before opening the table
exec sql
  OPEN DATABASE southwind;
exec sql
  SET ENCRYPTION TO "key_1,key_2,key_3";
exec sql
  SELECT * FROM customers;
// Or by appending the key to the filename
exec sql
  OPEN DATABASE southwind;
exec sql
  SELECT * FROM customers<key_1,key_2,key_3>;
SQL UPDATE
Used to update data in a table via SQL.
// The three part key can be specified using a
// default encryption key before opening the table
exec sql
  OPEN DATABASE southwind;
exec sql
  SET ENCRYPTION TO "key_1,key_2,key_3";
exec sql
  UPDATE customers
  SET companyname='Recital Corporation Inc.'
  WHERE customerid='RECIT';
// Or by appending the key to the filename
exec sql
  OPEN DATABASE southwind;
exec sql
  UPDATE customers<key_1,key_2,key_3>
  SET companyname='Recital Corporation Inc.'
  WHERE customerid='RECIT';

Summary

Recital offers a range of ways to keep your data secure. These start with the Operating System read/write permissions, which can be further refined to the level of table I/O operations and then field access in the Dictionary based Security and Protection rules. The Dictionary also provides the means to protect the integrity of the data via data validation and to assist in correct data entry through the use of choicelists, help messages and picture clauses etc. A further role of the Dictionary is in the provision of Table Triggers, which can be used to enable a programmatic response to table operations to add in additional checks or audit trails. For the most sensitive data, DES3 encryption is the ultimate protection: encrypting the physical data on the disk and only permitting table access on the production of the three part encryption key.

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Recital is a rich and versatile product with many ways to do the same thing. Developers usually write code in the way that they are accustomed to without paying much attention to how this will perform in a multi-user environment with large amounts of users and transactions. The best way to optimize Recital applications is to use the built-in tuning capabilities introduced in Recital 10.

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A quick tip for optimizing TCP performance on linux.

edit /etc/sysctl.conf add the lines:

If using gigabit ethernet:

net.ipv4.tcp_mem= 98304 131072 196608
net.ipv4.tcp_window_scaling=1
net.core.wmem_default = 65536
net.core.rmem_default = 65536
net.core.wmem_max=8388608

To reload these use:

# sysctl -p

If using infiniband:

net.ipv4.tcp_window_scaling=1
net.ipv4.tcp_timestamps=0
net.ipv4.tcp_sack=0
net.ipv4.tcp_rmem=10000000 10000000 10000000
net.ipv4.tcp_wmem=10000000 10000000 10000000
net.ipv4.tcp_mem=10000000 10000000 10000000
net.core.rmem_max=524287
net.core.wmem_max=524287
net.core.rmem_default=524287
net.core.wmem_default=524287
net.core.optmem_max=524287
net.core.netdev_max_backlog=300000

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