Yes, i have a presentation, and i have to explain how mac os x handles process synchronization.What techniques does it uses. For example linux was a nonpreemptive kernel, meaning that a process running in kernel mode could not be preempted, even if a higher-priority process became available, now linux is fully preemptive, and provides spinlocks and semaphores. Aug 08, 2013  However, since synchronization in the kernel is somewhat different from locking in an application this chapter does provide a brief overview to help ease the transition, or for experienced kernel developers, to refresh your memory. As an OS X kernel programmer, you have many choices of synchronization mechanisms at your disposal. What is data synchronization? Data synchronization ensures accurate, secure, compliant data and successful team and customer experiences. It assures congruence between each source of data and its different endpoints. As data comes in, it is cleaned, checked for errors, duplication, and consistency before being put to use.

• Data Synchronization For Os X 8

Data synchronization is the process of establishing consistency among data from a source to a target data storage and vice versa and the continuous harmonization of the data over time. It is fundamental to a wide variety of applications, including file synchronization and mobile device synchronization e.g., for PDAs.^[1][2]Synchronization can also be useful in encryption for synchronizing Public Key Servers.^[3]

File-based solutions[edit]

There are tools available for file synchronization, version control (CVS, Subversion, etc.), distributed filesystems (Coda, etc.), and mirroring (rsync, etc.), in that all these attempt to keep sets of files synchronized. However, only version control and file synchronization tools can deal with modifications to more than one copy of the files.

• File synchronization is commonly used for home backups on external hard drives or updating for transport on USB flash drives. The automatic process prevents copying already identical files, thus can save considerable time relative to a manual copy, also being faster and less error prone.^[4]
• Version control tools are intended to deal with situations where more than one user attempts to simultaneously modify the same file, while file synchronizers are optimized for situations where only one copy of the file will be edited at a time. For this reason, although version control tools can be used for file synchronization, dedicated programs require less overhead.
• Distributed filesystems may also be seen as ensuring multiple versions of a file are synchronized. This normally requires that the devices storing the files are always connected, but some distributed file systems like Coda allow disconnected operation followed by reconciliation. The merging facilities of a distributed file system are typically more limited than those of a version control system because most file systems do not keep a version graph.
• Mirror (computing): A mirror is an exact copy of a data set. On the Internet, a mirror site is an exact copy of another Internet site. Mirror sites are most commonly used to provide multiple sources of the same information, and are of particular value as a way of providing reliable access to large downloads.

Theoretical models[edit]

Several theoretical models of data synchronization exist in the research literature, and the problem is also related to the problem of Slepian–Wolf coding in information theory. The models are classified based on how they consider the data to be synchronized.

Unordered data[edit]

Data Synchronization For Os X 8

The problem of synchronizing unordered data (also known as the set reconciliation problem) is modeled as an attempt to compute the symmetric difference${\displaystyle S_A\oplus S_B=(S_A-S_B)\cup (S_B-S_A)}$ between two remote sets ${\displaystyle S_A}$and ${\displaystyle S_B}$ of b-bit numbers.^[5] Some solutions to this problem are typified by: Goldwave for mac os x.

Wholesale transfer

In this case all data is transferred to one host for a local comparison.

Timestamp synchronization

In this case all changes to the data are marked with timestamps. Synchronization proceeds by transferring all data with a timestamp later than the previous synchronization.^[6]

Mathematical synchronization

In this case data are treated as mathematical objects and synchronization corresponds to a mathematical process.^[5][7][8]

Ordered data[edit]

In this case, two remote strings ${\displaystyle {\sigma }_A}$ and ${\displaystyle {\sigma }_B}$ need to be reconciled. Typically, it is assumed that these strings differ by up to a fixed number of edits (i.e. character insertions, deletions, or modifications). Then data synchronization is the process of reducing edit distance between ${\displaystyle {\sigma }_A}$ and ${\displaystyle {\sigma }_B}$, up to the ideal distance of zero. This is applied in all filesystem based synchronizations (where the data is ordered). Many practical applications of this are discussed or referenced above.

It is sometimes possible to transform the problem to one of unordered data through a process known as shingling (splitting the strings into shingles^{[clarification needed]}).^[9]

Error handling[edit]

In fault-tolerant systems, distributed databases must be able to cope with the loss or corruption of (part of) their data. The first step is usually replication, which involves making multiple copies of the data and keeping them all up to date as changes are made. However, it is then necessary to decide which copy to rely on when loss or corruption of an instance occurs.

To get the InstallESD.DMG, go to Application right mouse on OS X Yosemite select “ Show Package Contents“. OS X – Mavericks, Mountain Lion, and Lion can be downloaded through Torrent method:Firstly, Get or Folx Pro , then use following torrent file to download the OS X version you desire. After downloading, OS X Yosemite Installer will appear in /Applications. Mac os x update.

The simplest approach is to have a single master instance that is the sole source of truth. Changes to it are replicated to other instances, and one of those instances becomes the new master when the old master fails.

Paxos and Raft are more complex protocols that exist to solve problems with transient effects during failover, such as two instances thinking they are the master at the same time.

Secret sharing is useful if failures of whole nodes are very common. This moves synchronization from an explicit recovery process to being part of each read, where a read of some data requires retrieving encoded data from several different nodes. If corrupt or out-of-date data may be present on some nodes, this approach may also benefit from the use of an error correction code.

DHTs and Blockchains try to solve the problem of synchronization between many nodes (hundreds to billions).

See also[edit]

• SyncML, a standard mainly for calendar, contact and email synchronization

References[edit]

1. ^Agarwal, S.; Starobinski, D.; Ari Trachtenberg (2002). 'On the scalability of data synchronization protocols for PDAs and mobile devices'. IEEE Network. 16 (4): 22–28. CiteSeerX10.1.1.12.5572. doi:10.1109/MNET.2002.1020232.
2. ^S. Braun; R. Carbon; M. Naab (2016). 'Piloting a Mobile-App Ecosystem for Smart Farming'. IEEE Software. 33 (4): 9–14. doi:10.1109/MS.2016.98.
3. ^'sks.dnsalias.net'. Archived from the original on 2007-03-05. Retrieved 2019-07-17.
4. ^A. Tridgell (February 1999). 'Efficient algorithms for sorting and synchronization'(PDF). PhD thesis. The Australian National University.Cite journal requires journal= (help)
5. ^ ^abMinsky, Y.; Ari Trachtenberg; Zippel, R. (2003). 'Set reconciliation with nearly optimal communication complexity'. IEEE Transactions on Information Theory. 49 (9): 2213–2218. CiteSeerX10.1.1.73.5806. doi:10.1109/TIT.2003.815784.
6. ^'Palm developer knowledgebase manuals'. Archived from the original on 2002-03-11. Retrieved 2007-01-09.
7. ^Ari Trachtenberg; D. Starobinski; S. Agarwal. 'Fast PDA Synchronization Using Characteristic Polynomial Interpolation'(PDF). IEEE INFOCOM 2002. doi:10.1109/INFCOM.2002.1019402.
8. ^Y. Minsky and A. Trachtenberg, Scalable set reconciliation, Allerton Conference on Communication, Control, and Computing, Oct. 2002
9. ^S. Agarwal; V. Chauhan; Ari Trachtenberg (November 2006). 'Bandwidth efficient string reconciliation using puzzles'(PDF). IEEE Transactions on Parallel and Distributed Systems. 17 (11): 1217–1225. doi:10.1109/TPDS.2006.148. Retrieved 2007-05-23.

SyncMate has the capability to combine sync of multiple devices, all on one app. It is also known for working on a plethora of mobile devices, from iPhones to Android phones; and it’s available to download on Mac and Windows computers.

Supported devices. It supports sync with Android, iOS, other Mac computers, MTP and mounted devices. Online accounts supported are iCloud, Dropbox, Google. Moreover, you can sync data on Mac OS X with Windows services also - Outlook, Office 365 Home and Business accounts (sync with One Drive also supported).

Sync options. The list of sync options is impressive as well. Starting from personal data to media files and folders. SyncMate offers several non-sync options like device mounting, SMS management, and others.

Pros of SyncMate: SyncMate is extremely easy to use, even for beginners. This sync software allows you to manage your SMS messages from a number of mobile devices. The interface is very pleasing, the speed at which the program syncs files is very speedy. Many users also rave about the excellent customer service.

Cons of SyncMate: There are two different versions of SyncMate: Free and Expert. Of course, the Expert edition offers many more features, but it will set you back around $40.

Conclusion. SyncMate is probably the most feature-rich featured app on this list and the only one that allows syncing data from numerous devices and accounts with Mac apps (iCal, Address Book, Music, etc.) directly without the necessity of using cloud sync.