{"id":139,"date":"2013-09-15T16:12:20","date_gmt":"2013-09-15T08:12:20","guid":{"rendered":"http:\/\/www.datarelab.com\/blog\/?p=139"},"modified":"2015-01-18T19:40:18","modified_gmt":"2015-01-18T11:40:18","slug":"vc%e8%8e%b7%e5%8f%96%e7%a1%ac%e7%9b%98%e7%89%a9%e7%90%86%e6%89%87%e5%8c%ba%e4%b8%8e%e9%80%bb%e8%be%91%e6%89%87%e5%8c%ba%e5%a4%a7%e5%b0%8f","status":"publish","type":"post","link":"https:\/\/www.datarelab.com\/blog\/Technical_literature\/139.html","title":{"rendered":"VC\u83b7\u53d6\u786c\u76d8\u7269\u7406\u6247\u533a\u4e0e\u903b\u8f91\u6247\u533a\u5927\u5c0f"},"content":{"rendered":"

 <\/p>\n

Used in conjunction with the\u00a0IOCTL_STORAGE_QUERY_PROPERTY<\/strong>\u00a0control code to retrieve the storage access alignment descriptor data for a device.<\/p>\n

Syntax<\/h3>\n
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C++<\/a><\/div>\n<\/div>\n
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<\/div>\n
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typedef<\/span> struct<\/span> _STORAGE_ACCESS_ALIGNMENT_DESCRIPTOR {\r\n  DWORD Version;\r\n  DWORD Size;\r\n  DWORD BytesPerCacheLine;\r\n  DWORD BytesOffsetForCacheAlignment;\r\n  DWORD BytesPerLogicalSector;\r\n  DWORD BytesPerPhysicalSector;\r\n  DWORD BytesOffsetForSectorAlignment;\r\n} STORAGE_ACCESS_ALIGNMENT_DESCRIPTOR, *PSTORAGE_ACCESS_ALIGNMENT_DESCRIPTOR;\r\n\r\n<\/pre>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n
Members<\/h3>\n
Version<\/strong><\/p>\n
Contains the size of this structure, in bytes. The value of this member will change as members are added to the structure.<\/p>\n
Size<\/strong><\/p>\n
Specifies the total size of the data returned, in bytes. This may include data that follows this structure.<\/p>\n
BytesPerCacheLine<\/strong><\/p>\n
The number of bytes in a cache line of the device.<\/p>\n
BytesOffsetForCacheAlignment<\/strong><\/p>\n
The address offset necessary for proper cache access alignment, in bytes.<\/p>\n
BytesPerLogicalSector<\/strong><\/p>\n
The number of bytes in a logical sector of the device.<\/p>\n
BytesPerPhysicalSector<\/strong><\/p>\n
The number of bytes in a physical sector of the device.<\/p>\n
BytesOffsetForSectorAlignment<\/strong><\/p>\n
The logical sector offset within the first physical sector where the first logical sector is placed, in bytes.<\/p>\n
Example: Offset = 3 Logical sectors<\/p>\n
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<\/div>\n
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<\/div>\n
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+---------+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+\r\n|LBA      |##|##|##|00|01|02|03|04|05|06|07|08|09|10|11|12|13|14|15|16|17|\r\n+---------+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+\r\n|Physical |                       |                       |                ...\r\n|Sector   |           0           |           1           |           2\r\n+---------+-----------------------+-----------------------+---------------\r\n<\/pre>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n
In this example,\u00a0BytesOffsetForSectorAlignment = 3 * BytesPerLogicalSector.<\/p>\n
Examples<\/h3>\n
The following sample code retrieves a\u00a0STORAGE_ACCESS_ALIGNMENT_DESCRIPTOR<\/strong>\u00a0structure and displays the physical sector size and the logical sector size if it differs from the physical sector size.<\/p>\n
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C++<\/a><\/div>\n<\/div>\n
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#include <windows.h>\r\n#include <stdio.h>\r\n\r\nDWORD DetectSectorSize( WCHAR * devName, PSTORAGE_ACCESS_ALIGNMENT_DESCRIPTOR pAlignmentDescriptor);\r\n\r\nDWORD wmain()\r\n {\r\n  DWORD                               Error     = NO_ERROR;\r\n  STORAGE_ACCESS_ALIGNMENT_DESCRIPTOR Alignment = {0};\r\n  WCHAR                               szDisk[]  = L\"\\\\\\\\.\\\\PhysicalDrive0\"<\/span>;\r\n\r\n  Error = DetectSectorSize(szDisk, &Alignment); if<\/span> (Error)\r\n   {\r\n    wprintf(L\"Error %lu encountered while querying alignment.\\n\"<\/span>, Error); return<\/span> Error;\r\n   }\r\n\r\n  wprintf(L\"Disk %s Properties\\n\"<\/span>, (WCHAR*) szDisk); if<\/span> (Alignment.BytesPerLogicalSector < Alignment.BytesPerPhysicalSector)\r\n   {\r\n    wprintf(L\"  Emulated sector size is %lu bytes.\\n\"<\/span>, Alignment.BytesPerLogicalSector);\r\n    wprintf(L\"  Physical sector size is %lu bytes.\\n\"<\/span>, Alignment.BytesPerPhysicalSector);\r\n   } else<\/span> {\r\n    wprintf(L\"  Physical sector size is %lu bytes.\\n\"<\/span>, Alignment.BytesPerPhysicalSector);\r\n   } return<\/span> 0;\r\n }\r\n\r\nDWORD DetectSectorSize( WCHAR * devName, PSTORAGE_ACCESS_ALIGNMENT_DESCRIPTOR pAlignmentDescriptor)\r\n {\r\n  DWORD                  Bytes   = 0;\r\n  BOOL                   bReturn = FALSE;\r\n  DWORD                  Error   = NO_ERROR;\r\n  STORAGE_PROPERTY_QUERY Query;\r\n  \r\n  ZeroMemory(&Query, sizeof<\/span>(Query));\r\n\r\n  HANDLE  hFile = CreateFileW( devName,\r\n                               STANDARD_RIGHTS_READ, \r\n                               FILE_SHARE_READ | FILE_SHARE_WRITE,\r\n                               NULL, \r\n                               OPEN_EXISTING, \r\n                               FILE_ATTRIBUTE_NORMAL,\r\n                               NULL); if<\/span> (hFile==INVALID_HANDLE_VALUE)\r\n   {\r\n    Error=GetLastError(); return<\/span> Error;\r\n   }\r\n\r\n  Query.QueryType  = PropertyStandardQuery;\r\n  Query.PropertyId = StorageAccessAlignmentProperty;\r\n      \r\n  bReturn = DeviceIoControl( hFile, \r\n                             IOCTL_STORAGE_QUERY_PROPERTY, \r\n                             &Query, sizeof<\/span>(STORAGE_PROPERTY_QUERY), \r\n                             pAlignmentDescriptor, sizeof<\/span>(STORAGE_ACCESS_ALIGNMENT_DESCRIPTOR), \r\n                             &Bytes,\r\n                             NULL); if<\/span> (bReturn == FALSE)\r\n   {\r\n    Error=GetLastError();\r\n   }\r\n\r\n  CloseHandle(hFile); return<\/span> Error;\r\n\r\n }\r\n\r\n\r\n<\/pre>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n
Requirements<\/h3>\n\n\n\n\n\n
\n
Minimum supported client<\/p>\n<\/th>\n
Windows\u00a0Vista [desktop apps only]<\/td>\n<\/tr>\n
\n
Minimum supported server<\/p>\n<\/th>\n
Windows Server\u00a02008 [desktop apps only]<\/td>\n<\/tr>\n
\n
Header<\/p>\n<\/th>\n
WinIoCtl.h (include Windows.h)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
 <\/p>\n","protected":false},"excerpt":{"rendered":"
  Used in conjunction with the\u00a0IOCTL_STORAGE_QUERY […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[168],"class_list":["post-139","post","type-post","status-publish","format-standard","hentry","category-Technical_literature","tag-vc"],"views":1936,"_links":{"self":[{"href":"https:\/\/www.datarelab.com\/blog\/wp-json\/wp\/v2\/posts\/139","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.datarelab.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.datarelab.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.datarelab.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.datarelab.com\/blog\/wp-json\/wp\/v2\/comments?post=139"}],"version-history":[{"count":0,"href":"https:\/\/www.datarelab.com\/blog\/wp-json\/wp\/v2\/posts\/139\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.datarelab.com\/blog\/wp-json\/wp\/v2\/media?parent=139"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.datarelab.com\/blog\/wp-json\/wp\/v2\/categories?post=139"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.datarelab.com\/blog\/wp-json\/wp\/v2\/tags?post=139"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}