This manual provides users with a fast guide of Chipsee Industrial Computer (Abbreviate as IPC) about Linux Qt 5.5 OS development. Through this manual, users can quickly understand the hardware resources; users can build a complete compilation of Linux development environment; users can debug Linux Qt 5.5 OS via serial and Internet.
Securecrt 5.5 serial number
You can refer to the RS232/RS485/CAN Connector section under the EPC/PPC-A7-070HB-C manual to understand the serial ports of the IPC.The debug serial port of Chipsee Industrial Computer is the first RS232 port. You can use it to debug directly, and the default user and password is [root/root].You can use RS232_1_TXD, RS232_1_RXD, GND.
You can get the Prebuilt Files Package for each model from links mentioned at the beginning of this documentation.You can also get the Prebuilt Files Package from the DVD in /Linux Qt 5.5/Prebuilds folder. However, it may be outdated so alwayscompare the versions (the last number in the filename is the release date).
The default serial port configuration is 2 x RS232, 2 x RS485, 1 x RS485 which is shared with Bluetooth. Contact us if you need help with changing the default serial port configuration
The Catalyst 4000 with Supervisor Engine I chassis serial number on the Catalyst 4003, 2948G, and 2980G is not readable through a CLI command. The serial number that appears in the show version command output in the example in this section is the serial number of the Supervisor Engine. The actual serial number appears on a sticker on the outside of the chassis.
On the Catalyst 4500/4000 Supervisor 2, the chassis serial number is available via CLI in versions 5.5(10), 6.3(2), and later versions. In earlier versions, theshow versioncommand shows the Supervisor Engine serial number in the place of the chassis serial number. To obtain the serial number of the chassis in these earlier versions, check the external sticker on the chassis.
Use theshow versioncommand to determine the chassis serial number and switch model type, as the example here shows. You find all switch stack members, chassis, and serial number information in the output:
Changes the number of file descriptors available to mysqld. You should try increasing the value of this option if mysqld gives you the error Too many open files. mysqld uses the option value to reserve descriptors with setrlimit(). If the requested number of file descriptors cannot be allocated, mysqld writes a warning to the error log.
mysqld may attempt to allocate more than the requested number of descriptors (if they are available), using the values of max_connections and table_cache to estimate whether more descriptors will be needed.
The number of outstanding connection requests MySQL can have. This comes into play when the main MySQL thread gets very many connection requests in a very short time. It then takes some time (although very little) for the main thread to check the connection and start a new thread. The back_log value indicates how many requests can be stacked during this short time before MySQL momentarily stops answering new requests. You need to increase this only if you expect a large number of connections in a short period of time.
The maximum number of locks that can be active for a BDB table (10,000 by default). You should increase this value if errors such as the following occur when you perform long transactions or when mysqld has to examine many rows to calculate a query:
This is a per-table limit on the number of rows to queue when handling INSERT DELAYED statements. If the queue becomes full, any client that issues an INSERT DELAYED statement waits until there is room in the queue again.
This variable indicates the number of digits by which to increase the scale of the result of division operations performed with the / operator. The default value is 4. The minimum and maximum values are 0 and 30, respectively. The following example illustrates the effect of increasing the default value.
The number of seconds the server waits for activity on an interactive connection before closing it. An interactive client is defined as a client that uses the CLIENT_INTERACTIVE option to mysql_real_connect(). See also wait_timeout.
This value is an approximation because some space in the key buffer is allocated internally for administrative structures. Factors that influence the amount of overhead for these structures include block size and pointer size. As block size increases, the percentage of the key buffer lost to overhead tends to decrease. Larger blocks results in a smaller number of read operations (because more keys are obtained per read), but conversely an increase in reads of keys that are not examined (if not all keys in a block are relevant to a query).
If there are more than this number of interrupted connections from a host, that host is blocked from further connections. You can unblock blocked hosts with the FLUSH HOSTS statement. If a connection is established successfully within fewer than max_connect_errors attempts after a previous connection was interrupted, the error count for the host is cleared to zero. However, once a host is blocked, the FLUSH HOSTS statement is the only way to unblock it.
Do not start more than this number of threads to handle INSERT DELAYED statements. If you try to insert data into a new table after all INSERT DELAYED threads are in use, the row is inserted as if the DELAYED attribute wasn't specified. If you set this to 0, MySQL never creates a thread to handle DELAYED rows; in effect, this disables DELAYED entirely.
This variable limits the total number of prepared statements in the server. It can be used in environments where there is the potential for denial-of-service attacks based on running the server out of memory by preparing huge numbers of statements. If the value is set lower than the current number of prepared statements, existing statements are not affected and can be used, but no new statements can be prepared until the current number drops below the limit. The default value is 16,382. The permissible range of values is from 0 to 1 million. Setting the value to 0 disables prepared statements. This variable was added in MySQL 5.0.21.
The number of times that any given stored procedure may be called recursively. The default value for this option is 0, which completely disables recursion in stored procedures. The maximum value is 255.
How the server treats NULL values when collecting statistics about the distribution of index values for MyISAM tables. This variable has three possible values, nulls_equal, nulls_unequal, and nulls_ignored. For nulls_equal, all NULL index values are considered equal and form a single value group that has a size equal to the number of NULL values. For nulls_unequal, NULL values are considered unequal, and each NULL forms a distinct value group of size 1. For nulls_ignored, NULL values are ignored.
The number of seconds to wait for more data from a connection before aborting the read. This timeout applies only to TCP/IP connections, not to connections made through Unix socket files, named pipes, or shared memory. When the server is reading from the client, net_read_timeout is the timeout value controlling when to abort. When the server is writing to the client, net_write_timeout is the timeout value controlling when to abort. See also slave_net_timeout.
The number of seconds to wait for a block to be written to a connection before aborting the write. This timeout applies only to TCP/IP connections, not to connections made using Unix socket files, named pipes, or shared memory. See also net_read_timeout.
The number of files that the operating system permits mysqld to open. This is the real value permitted by the system and might be different from the value you gave using the --open-files-limit option to mysqld or mysqld_safe. The value is 0 on systems where MySQL can't change the number of open files.
Controls the heuristics applied during query optimization to prune less-promising partial plans from the optimizer search space. A value of 0 disables heuristics so that the optimizer performs an exhaustive search. A value of 1 causes the optimizer to prune plans based on the number of rows retrieved by intermediate plans. This variable was added in MySQL 5.0.1.
The maximum depth of search performed by the query optimizer. Values larger than the number of relations in a query result in better query plans, but take longer to generate an execution plan for a query. Values smaller than the number of relations in a query return an execution plan quicker, but the resulting plan may be far from being optimal. If set to 0, the system automatically picks a reasonable value. If set to 63, the optimizer switches to the algorithm used in MySQL 5.0.0 (and previous versions) for performing searches. This variable was added in MySQL 5.0.1.
The current number of prepared statements. (The maximum number of statements is given by the max_prepared_stmt_count system variable.) This variable was added in MySQL 5.0.21. In MySQL 5.0.32, it was converted to the global Prepared_stmt_count status variable.
The purpose of these variables is to support replication of the RAND() function. For statements that invoke RAND(), the master passes two values to the slave, where they are used to seed the random number generator. The slave uses these values to set the session variables rand_seed1 and rand_seed2 so that RAND() on the slave generates the same value as on the master.
If set to 0, MySQL aborts SELECT statements that are likely to take a very long time to execute (that is, statements for which the optimizer estimates that the number of examined rows exceeds the value of max_join_size). This is useful when an inadvisable WHERE statement has been issued. The default value for a new connection is 1, which permits all SELECT statements. 2ff7e9595c
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