Jerk is what makes your printer shake. It is a speed difference between two moves, which can be reached without acceleration. So why do you want jerk and what does it influence? The first thing it influences is the starting speed. It is 50% of the allowed jerk. So if you have a jerk of 20, the first move will start with 10mm/s. The other thing jerk controls is the join speed for consecutive segments. In the figure above you see two examples. The jerk is the difference of the two speeds. Example 1 shows a jerk, that is higher then allowed. In this case, the path planner will reduce the speed to match exactly the maximum allowed speed. Example 2 has a lower directional change, so the jerk is within allowed limits and the planner allows a full speed move through the edge. The jerk is set these two values:

#define MAX_JERK 20.0
#define MAX_ZJERK 0.3

MAX_JERK is for x/y axis moves and MAX_ZJERK for moves in Z direction. You want high jerk values, because

printing time is reduced.
print shows less blobs.

You want low jerk values, because

it causes less mechanical stress to your printer.
moves are smoother.
filament has better adhesion at directional changes.
reduces printer noise.
you loose steps with higher values.

You see, it is balance between your personal priorities. The only simple thing is z-jerk, which has nearly no influence. It only reduces the time for z-moves, but has no effect on quality.

Symbian Rom Rpkg |link| -

In the early days of Symbian hacking, archivists preserved the Z: drive via simple file-structure folders, referred to as a . While functional, raw dumps were highly fragmented and easily corrupted. To streamline OS installation inside emulation environments, developers created the RPKG (ROM Packager) file format to unify thousands of micro-system files into a single, cohesive payload. Technical Specification of the RPKG Format

hstsethi/awesome-symbian: An Awesome List about ... - GitHub

Following the header, the file maps out each constituent asset from the original Z: drive. For every single file included, the RPKG lists:

Inject RomPatcher+ directly into the firmware files so the device is automatically "hacked" upon flashing, allowing unsigned apps to run. symbian rom rpkg

The file begins with a distinct magic identifier that declares its versioning layout: Data Field Description char[4] RPKG (Version 1) or RPK2 (Version 2) Major Version char Tracks core format revisions Minor Version char Minor feature flag updates Build Version short The compiled build revision number File Count uint32_t Total number of system entries inside the package Header Size uint32_t Specific to RPK2 ; tracks offset bounds Machine UID uint32_t Specific to RPK2 ; hardware profile identifier 2. The Entry Sections

When flashed, the phone’s firmware writer extracts each file to the virtual Z:\ drive (ROM portion of the filesystem).

Which is it running (S60v3, S60v5, Symbian^3, Belle)? In the early days of Symbian hacking, archivists

stands for ROM Package . Unlike a standard SIS file (which installs to the phone’s internal storage or memory card), an RPKG file is designed to be flashed directly into the phone’s firmware partition (the Read-Only Memory, or ROM).

(often stylized as *.rpkg ) stands informally for "Resource Package" or "ROM Package." If the ROM is a fortress, the RPKG file is the architectural blueprint.

In Nokia's terminology, the combination of these files tailored for a specific region or network carrier is managed by a configuration skeleton. This is where the RPKG comes into play. Understanding the RPKG File Format An file is a Release Package Configuration file . The file begins with a distinct magic identifier

Depending on the specific Symbian generation and target device you want to emulate, system files are processed using two primary methods: Metric / Feature RPKG Packaged Method ( .rpkg ) Raw Dump Folder Structure A single, unified uncompressed archive file. A multi-nested collection of open folders and raw files. Target Architecture Optimized heavily for S60v3, S60v5, and Symbian^3 . Used primarily for N-Gage (Classic/QD), S60v1, and S60v2 . Storage Signature Uses explicit byte offset headers ( RPKG / RPK2 ).

: Contents are repackaged without compression to ensure the emulator can access critical system libraries and servers instantly.

Some popular sources for Symbian ROMs and RPKGs include: