HFS + 10.6 8.1 Alunos: André de Freitas Smaira Alunos: Guilherme Pereira Gomes Alunos: Rodrigo Brunelli Rodrigues Alunos: Thereza Cury Fortunato

Hierarchical File System Plus (Apple Inc.)

Índice De HFS para HFS+ Evolução Estrutura Comparação Outros S.O.

De HFS para HFS+ 1985 - HFS - Mac System 1.0 1998 - HFS+ - Mac OS 8.1 Suporta arquivos maiores (bloco de endereço de 32-bit ao invés de 16-bit) Unicode ao invés de Mac OS Roman para nomes de arquivos e diretórios Codificação de caracteres UTF-16 255 caracteres para cada nome ao invés de 31 caracteres Falar que o hfs+ é usado em todos os dispositivos da aple.

Evolução 24/01/1984 - Mac System 1.0 - Macintosh File System (MFS) 09/1985 - Mac System 1.0 - Hierarchical File System (HFS) 19/01/1998 - Mac OS 8.1 - Hierarchical File System Plus (HFS+) 11/11/2002 - Mac OS X Jaguar 10.2.3 Server - Hierarchical File System Journaling (HFSJ) 24/10/2003 - Mac OS X Panther 10.3 - Hierarchical File System X (HFSX) 29/04/2005 - Mac OS X Tiger 10.4 - Segurança baseada em lista de controle de acesso 28/08/2009 - Mac OS X Snow Leopard 10.6 - Sistema de compressão de arquivos Macintosh File System (MFS) – criado para guardar arquivos em Disquetes de 400k. MFS foi importante por introduzir resource forks que permite o armazenamento de daos estruturados, e por armazenar metadados necessários ao funcionamento da interáce gráfica. MFS é chamado de flat file system pois não suporta diretórios hierárquicos. As pastas eram visiveis na janela de busca, mas não nas caixas de diálogo. HFS – Desenvolvido para computadores q rodam Mac OS Journaling File System - LOG de mudanças no sistema de arquivos antes de escrever no disco. Log circular alocado em uma área especial do sistema de arquivos. Melhor probabilidade de não corrupção no caso de travar ou faltar energia, e uma recuperação mais rápida, pois não necessita verificar todo o disco, somente aqueles que pertenciam a um log que não fora fechado devidamente. HFSX – Extensão do HFS+ com algumas diferenças como possibilidade de case sensitive Mac OS X 10.4 - totalmente compatível com outros SO’s

Estrutura Blocos lógicos (ou setores, geralmente 512 bytes) e Blocos de Alocação (32-bit) Invólucro para volumes antigos funcionarem no novo modelo 3 Árvores B (catálogo de arquivos, extensão para overflow’s no catálogo de arquivos, atributos) Atualmente não existe modo fácil do MacOS salvar em discos com padrão NTFS do Windows, mas consegue se comunicar com o FAT. The Attributes File is a new B-tree in HFS Plus that does not have a corresponding structure in HFS. The Attributes File can store three different types of 4 KB records: Inline Data Attribute records, Fork Data Attribute records and Extension Attribute records. Inline Data Attribute records store small attributes that can fit within the record itself. Fork Data Attribute records contain references to a maximum of eight extents that can hold larger attributes. Extension Attributes are used to extend a Fork Data Attribute record when its eight extent records are already used.

Comparação Tamanho máximo do arquivo Tamanho máximo do volume exFAT (2006): 16 EiB = 264 bytes exFAT (2006): 64 ZiB = 277 bytes HFS+ (1998): 8 EiB = 263 bytes NTFS (1993): 16 TiB = 244 bytes NTFS (1993): 256 TiB = 248 bytes FAT16 (1984): 4 GiB = 232 bytes HFS (1985): 2 TiB = 241 bytes FAT32 (1996): 4 GiB = 232 bytes FAT32 (1996): 2 TiB = 241 bytes HFS (1985): 2 GiB = 231 bytes EiB = Exbibyte ZiB = Zebibyte

Outros S.O. O kernel do Linux inclui um módulo HFS+. Mas em HDs com capacidade maior que 2TB foram corrompidos pelos drivers, consequentemente distribuições como Ubuntu e Debian pararam de permitir HDs HFS+ com essa capacidade. Em 2011 um projeto do Google Summer of Code, foi idealizado para implementar drivers de escrita para HFS+ e foi aceito pela Linux Foundation. Em Janeiro de 2012, a Apple lançou um driver apenas para leitura para Windows XP, Vista e 7. Linux The Linux kernel includes the hfsplus module[12] for mounting HFS+ filesystems. HFS+ fsck and mkfs have been ported to Linux and are part of the hfsprogs package.[13] In 2009, these drivers were diagnosed to be corrupting HFS+ drives with a capacity greater than 2 TB.[14] Consequently, Linux distributions such as Debian and Ubuntu also stopped allowing mounting of HFS+ drives or partitions greater than 2 TB.[15] As of February 2011, work is in progress to lift this restriction.[16] The Linux HFS+ kernel driver has support to read and write to HFS+ non-journaled drives/partitions but only has read support of journaled HFS+. Journaling is a redundant behavior of a filesystem that helps protect against data loss. If planning to write to an HFS+ partition then drive journaling must be turned off in Mac OS X.[17] A Google Summer of Code project to implement write-support to journalled HFS+ [18] was accepted by the Linux Foundation in 2011. Towards the beginning of the time frame (April 2011), Netgear released the source code of one of their NAS appliances, which included an implementation of journalled HFS+ write-support based on an earlier kernel. The student, Naohiro Aota, was to review and work on porting that forward to current kernel. However the style and level of work was found to be unsatisfactory and he was failed from the scheme at mid-term evaluation. The mentor, Hin-Tak Leung, eventually did the code-review and porting and posted the result (untested) [19], at [20]. Windows As of January 2012, Apple has only released read-only HFS+ drivers for Windows XP, Windows Vista, and Windows 7 as part of the Boot Camp software in Mac OS X 10.6. This means users on these systems can read data on the HFS+ drive, but not write to them. Microsoft has created an HFS+ driver for the Xbox 360 mainly for the purpose of reading HFS+ formatted iPods. A free (GPL) alternative is HFSExplorer written by Erik Larsson.[21] HFSExplorer is an application for viewing and extracting files from an HFS+ volume (Mac OS Extended) or an HFSX volume (Mac OS Extended, Case-sensitive) located either on a physical disk, on a .dmg disk image, or in a raw file system dump. However HFSExplorer can only read, but not write to HFS formatted volumes. A free and opensource software – jHFSplus, based on HFSExplorer and jpfm – can be used to mount hfs/hfs+ partitions as read-only virtual folders.[22] A freeware plugin for Total Commander exists, that can read, amongst others, HFS and HFS+ filesystems.[23] A freeware DiskInternals Linux Reader, can be used to extract/save folders/files out of HFS and HFS+ Hard Drives/Partitions.

Referências http://en.wikipedia.org/wiki/HFS_Plus (Acessado em 05/04/2012) http://en.wikipedia.org/wiki/Journaling_file_system (Acessado em 01/04/2012) http://en.wikipedia.org/wiki/OS_X (Acessado em 01/04/2012) http://en.wikipedia.org/wiki/Mac_OS_X_v10.2 (Acessado em 01/04/2012) http://forums.macrumors.com/showthread.php?t=1207791 (Acessado em 05/04/2012) http://www.conversioncenter.net/bits-and-bytes-conversion (Acessado em 05/04/2012) http://en.wikipedia.org/wiki/Macintosh_File_System (Acessado em 13/04/2012)