grIP v1.3.2

   grIP version 1.3.2 fixes a bug: the scan no longer stops if a "host is down" error is encountered.

The latest version can be downloaded from here, and the signature from here.

grIP v1.3.1

  grIP version 1.3.1 has even better shuffling of the scan space, with even lower memory usage and escapes "[" and "]" as it should to avoid ambiguity in received data.

The latest version can be downloaded from here, and the signature from here.

CD Recording Modes

I wanted to preserve this knowledge that I found in a webpage that I can no longer find online along with some info from Wikipedia.

DAO (Disc At Once)

In this mode, the entire CD is written in a single continuous session, and no additional data can be added later. DAO has the following advantages:

• Maximizes the capacity of the CD.
• Provides complete control over the CD layout.
• Allows user-defined gaps between audio tracks.
• The only mode that enables writing to unused R-W sub-channels.
• Supports extended features like CD+G and CD-Text.
• Allows for seamless audio tracks with no gaps (important for progressive rock, trance, and other music genres).

For audio CDs, DAO is particularly valuable because it allows for "hidden tracks" by placing audio in the pre-gap before the first track. This pre-gap audio can only be accessed by rewinding from the start of the first track.

TAO (Track At Once)

Track At Once allows for adding tracks incrementally over time.

• The CD remains readable only in a recorder until it's finalized.
• Once finalized, no more data can be added.
• Creates a 2-second gap between tracks containing a few bytes that may be heard as noise in some audio players.
• The recording laser stops after each track, writing two run-out blocks (special sectors that mark the end of a track and provide a transition zone before the next track begins).
• When the next track is recorded, one link block (connector sector that contain addressing information to help the CD player transition between tracks) and four run-in blocks (special sectors that help the CD player's laser stabilize before reading the actual track data) are written.
• TAO discs can contain both data and audio simultaneously.
• Available in two writing modes:
• Mode 1 (optimized for computer data with strong error correction)
• Mode 2 XA (with less error correction, for multimedia content like audio and video)

SAO (Session At Once)

Session At Once is similar to DAO:

• All information is written in one go (session).
• Additional sessions can be added later.
• Within each session, the user has complete control over the CD layout

SAO is essentially a superset of DAO, with the main difference being that SAO allows for further writing to the disc.

Multiple sessions recorded with SAO can be read by computer drives, but sessions after the first are generally not readable by standard CD audio equipment.

PAO (Packet At Once)

Packet At Once is used for incremental writing where information is transferred to the CD in small "packets":

• Each packet consists of a few kilobytes.
• This approach makes buffer under-runs virtually impossible.
• Each packet has its own lead-in and lead-out, which consume 7 frames of CD space.
• PAO cannot be used for audio recording.

Multisession

Multisession recording uses TAO to allow adding data across multiple sessions:

• Each new session consumes approximately 15MB of disc space for session information.
• Sessions can be related to each other: Newer versions of files can "substitute" older versions existing in previous sessions.

CUE Sheet

CUE sheets can only be used with recorders that support the "send cue" command:

• The CD layout is described in a simple text file with a straightforward syntax.
• Particularly useful when writing audio CDs or complex CD layouts.

Example of CUE sheet format:

TRACK 01
AUDIO TITLE "Track01"
PERFORMER "Unknown Artist"
INDEX 01 00:00:00
TRACK 02
AUDIO TITLE "Track02"
PERFORMER "Unknown Artist"
INDEX 00 03:27:16
INDEX 01 03:28:50

Audio Master Quality Recording

This specialized recording method was introduced by Yamaha in 2002:

• Only available on select models like Yamaha's CRW3200 and CRW-F1 series, and Plextor's Premium 2.
• CD recorders with this feature are no longer manufactured.
• Uses the Disc-At-Once method, typically at 1x speed (though some recorders allow 4x and 8x).
• Creates longer pits and lands, reducing the total capacity of the disc.
• A 650MB CD can hold about 63 minutes instead of 74 minutes.
• A 700MB CD can hold about 68 minutes instead of 80 minutes.

Recovery Guide for Casio FX-5800P Calculator

In rare cases, the FX-5800P calculator may experience firmware corruption, displaying ROM!!!!! on startup. Here's a comprehensive guide to recover your calculator:

1. Remove all batteries from the calculator
2. Leave the calculator without batteries for at least 1 hour (some users report success with this simple step)
3. Reinstall the batteries and turn on the calculator
4. If the calculator still displays ROM!!!!!, proceed to the firmware recovery method.

Firmware Recovery Process

You'll need:

• Another properly functioning FX-5800P calculator
• A 3-pin data cable to connect both calculators

WARNING: The malfunctioning calculator must ALWAYS be set to OS UP Recv and the working calculator to OS UP Send. Reversing these roles will damage your working calculator.

WARNING: This will erase all data in the WORKING calculator, so back up any important information before proceeding.

On the Working FX-5800P (SENDER):

1. Simultaneously press AC/ON + MODE + 7 keys.
   The screen will display DIAGNOSTIC MODE, Factory use only.
2. Press the ← key, then press 9.
   
3. Press 2 to select OS UP Send.

On the Malfunctioning FX-5800P (RECEIVER):

1. Press the FILE key.

2. Select OS UP Recv.

After the transfer completes, the malfunctioning calculator should be working fine again.

Slow Query Monitoring in MySQL and MariaDB

To enable slow query monitoring in MySQL or MariaDB, run these commands in your client:

SET GLOBAL slow_query_log = 1;
SET GLOBAL long_query_time = 0.5;

This activates the slow query log and sets it to capture any queries taking longer than 0.5 seconds. You can adjust this threshold based on your performance requirements.

Slow queries will be logged to some file like:

/var/lib/mysql/*-slow.log

You can check or change that with:

SHOW VARIABLES LIKE 'slow_query_log_file';
SET GLOBAL slow_query_log_file = '/custom/path/slow-queries.log';

To make these changes permanent, add these lines to your my.cnf/my.ini file:

[mysqld]
slow_query_log = 1
long_query_time = 0.5
slow_query_log_file = /custom/path/slow-queries.log

To analyze slow queries, use:

mysqldumpslow /custom/path/slow-queries.log