Usenetfs: A Stackable File System for Large Article Directories

The Internet has grown much in popularity in the past few years. Numerous users read USENET newsgroups daily for entertainment, work, study, and more. USENET News servers have seen a gradual increase in the traffic exchanged between them, to a point where the hardware and software supporting the servers is no longer capable of meeting demand, at which point the servers begin 'dropping' articles they could not process. The rate of this increase has been faster than software or hardware improvements were able to keep up,resulting in much time and effort spent by administrators upgrading their news systems. One of the primary reasons for the slowness of news servers has been the need to process many articles in very large flat directories representing newsgroups such as control. cancel and misc.jobs.offered. A large portion of the resources is spent on processing articles in these few newsgroups. Most Unix directories are organized as a linear unsorted sequence of entries. Large news groups can have hundreds of thousands of articles in one directory, resulting in significant delays processing any single article. Usenetfs is a file system that rearranges the directory structure from being flat to one with small directories containing fewer articles. By breaking the structure into smaller directories, it improves the performance of looking for, creating, or deleting files, since these operations occur on smaller directories. Usenetfs takes advantage of article numbers; knowing that file names representing articles are composed of digits helps to bound the size of the smaller directories. Usenetfs improves overall performance by at least 22\%for average news servers; common news server operations such as looking up, adding, and deleting articles are sped up by as much as several orders of magnitude. Usenetfs was designed and implemented as a stackable Vnode layer loadable kernel module. It operates by 'encapsulating' a client file system with a layer of directory management. To the process performing directory operations through a mounted Usenetfs, all directories appear flat; but when inspecting the underlying storage that it manages, small directories are visible. Usenetfs is small and is transparent to the user. It requires no change to News software, to other file systems, or to the rest of the operating system. Usenetfs is more portable than other native kernel-based file systems because it interacts with the Vnode interface which is similar on many different platforms

Cryptfs: A Stackable Vnode Level Encryption File System

Data encryption has become an increasingly important factor in everyday work. Users seek a method of securing their data with maximum comfort and minimum additional requirements on their part; they want a security system that protects any files used by any of their applications, without resorting to application-specific encryption methods. Performance is an important factor to users since encryption can be time consuming. Operating system vendors want to provide this functionality but without incurring the large costs of developing a new file system. This paper describes the design and implementation of Cryptfs -- a file system that was designed as a stackable Vnode layer loadable kernel module. Cryptfs operates by 'encapsulating' a client file system with a layer of encryption transparent to the user. Being kernel resident, Cryptfs performs better than user-level or NFS based file servers such as CFS and TCFS. It is 2 to 37 times faster on micro-benchmarks such as read and write; this translates to 12-52\%application speedup, as exemplified by a large build. Cryptfs offers stronger security by basing its keys on process session IDs as well as user IDs, and by the fact that kernel memory is harder to access. Working at and above the vnode level, Cryptfs is more portable than a file system which works directly with native media such as disks and networks. Cryptfs can operate on top of any other native file system such as UFS/FFS and NFS. Finally, Cryptfs requires no changes to client file systems or remote servers

Performance of Size-Changing Algorithms in Stackable File Systems

Stackable file systems can provide extensible file system functionality with minimal performance overhead and development cost. However, previous approaches are limited in the functionality they provide. In particular, they do not support size-changing algorithms, which are important and useful for many applications, such as compression and security. We propose fast index files, a technique for efficient support of size-changing algorithms in stackable file systems. Fast index files provide a page mapping between file system layers in a way that can be used with any size-changing algorithm. Index files are designed to be recoverable if lost and add less than 0.1\% disk space overhead. We have implemented fast indexing using portable stackable templates, and we have used this system to build several example file systems with size-changing algorithms. We demonstrate that fast index files have very low overhead for typical workloads, only 2.3\% over other stacked file systems. Our system can deliver much better performance on size-changing algorithms than user-level applications, as much as five times faster

Variation of bioactive compounds in organic Ocimum basilicum L. during freeze-drying processing

Abstract Common basil (Ocimum basilicum L.), one of the most important aromatic perennial herbs due to its essential oil composition, belongs to Lamiaceae (Labiatae) family. Basil is an economically important herb and it is considered one of the finest aromatic herbs, being widely used as flavor in food industry. Basil samples were characterized in terms of chlorophyll content, total polyphenols, antioxidant activity, and volatile oil content. The fresh harvested leaves and the processed powder from leaves were hydro-distilled for 3 h in a Clevenger-type apparatus. The volatile oil was measured and collected for further GC-MS analysis. As drying technology, freeze-drying was used until the samples reached a loss of 85% from the fresh weigh, with the final dry matter content of 95.86%. Variations for the main constituents of volatile oil: 1,8-cineole, linalool, methyl chavicol, eugenol, α-bergamotene, and α-epi-cadinol were observed after processing

Sensorial evaluation of new developed biscuits enriched with organic apple and basil powders: preliminary study

Abstract The purpose of the study is to harness ingredients obtained from organic farming, in order to develop a new type of biscuits. Based on the original recipe, these were obtained from seeds and hemp flour and enriched with lyophilized organic apple (pieces and powder) and lyophilized organic basil powder. The organic powders were realized in the framework of the SusOrgPlus project at the Research Centre for Studies of Food Quality and Agricultural Products, and biscuits were obtained in the Bakery Pilot Station, both of University of Agronomic Sciences and Veterinary Medicine of Bucharest. The consumer acceptance testing was performed on 33 consumers and consists of the evaluation of general appearance, colour, taste, aroma, and consistency (Hedonic 5-point scale). The obtained results showed that the new biscuits enriched with lyophilized apple and basil powders were easily accepted by the consumers

A Stackable File System Interface For Linux

Linux is a popular operating system that is rapidly evolving due to being Open Source and having many developers. The Linux kernel comes with more than two dozen file systems, all of which are native: they access device drivers directly. Native file systems are harder to develop. Stackable file systems, however, are easier to develop because they use existing file systems and interfaces

SusOrganic, un proiect pentru dezvoltarea agriculturii ecologice

În practică, eficiența utilizării resurselor și calitatea produselor sunt adesea văzute ca antagoniști. SusOrganic este un proiect de cercetare integrator care va dezvolta soluții tehnice, proceduri standard de operare și ghiduri care sa conducă la creșterea calității produselor obținute prin astfel de tehnologii, reducând în același timp consumul de resurse, respectiv materii prime și energie. Includerea unor lideri din diverse domenii - oameni de știință specializati in productia alimentara, ingineri mecanici, ingineri de proces și control, fermieri și un comerciant cu amănuntul - din Europa Centrala, de Est, de Nord și Europa de Sud asigura faptul ca toate aspectele relevante pentru dezvoltarea standardelor de calitate, optimizarea proceselor și utilizarea eficientă a resurselor sunt abordate în mod adecvat și este asigurata relevanța proiectului în întreaga UE și în afara acesteia. Coordonator:University of Kassel, Germany Parteneri: Meridian Fruchthandelsgesellschaft mbH, Germany Swedish University of Agricultural Sciences, Sweden University of Agronomic Sciences and Veterinary Medicine of Bucharest, Romania SINTEF Energy Research, Norway University of Teramo, Italy University of Tuscia, Viterbo, Ital

Extending File Systems Using Stackable Templates

Extending file system functionality is not a new idea, but a desirable one nonetheless[6, 14, 18]. In the several years since stackable file systems were first proposed, only a handful are in use[12, 19]. Impediments to writing new file systems include the complexity of operating systems, the difficulty of writing kernel-based code, the lack of a true stackable vnode interface[14], and the challenges of porting one file system to another operating system. We advocate writing new stackable file systems as kernel modules. As a starting point, we propose a portable, stackable template file system we call Wrapfs (wrapper file system). Wrapfs is a canonical, minimal stackable file system that can be used as a pattern across a wide range of operating systems and file systems. Given Wrapfs, developers can add or modify only that which is necessary to achieve the desired functionality. Wrapfs takes care of the rest, and frees developers from the details of operating systems. Wrapfs templates ..

Performance of Size-Changing Algorithms in Stackable File Systems

Stackable file systems can provide extensible file system functionality with minimal performance overhead and development cost. However, previous approaches are limited in the functionality they provide. In particular, they do not support size-changing algorithms, which are important and useful for many applications, such as compression and security. We propose fast index files, a technique for efficient support of size-changing algorithms in stackable file systems. Fast index files provide a page mapping between file system layers in a way that can be used with any size-changing algorithm. Index files are designed to be recoverable if lost and add less than 0.1 % disk space overhead. We have implemented fast indexing using portable stackable templates, and we have used this system to build several example file systems with size-changing algorithms. We demonstrate that fast index files have very low overhead for typical workloads, only 2.3 % over other stacked file systems. Our system can deliver much better performance on size-changing algorithms than user-level applications, as much as five times faster.