浪潮AS5600( LANGCHAO AS5600 )
浪潮AS5600
参考价格：￥1200000
商家报价：￥1200000至￥1200000
高速缓存容量（MB）：96GB
接口：SSD、SAS、NL-SAS
RAID支持：0，1，5，6，10，50
主机通道：2-8个端口（iSCSI、 FCoE、以太网(10Gbit/s)） 2-16个端口（FC） 4-16个端口（以太网( 1Git/s)）
其他参数：控制器：双控制器（Active-Active），可升级扩展；硬盘数量：支持1200块硬盘；扩展柜：2U12、2U24、4U60；高级功能：同步/异步远程复制功能；MAID绿色节能技术；存储高可用功能；存储高可用功能；自动分层；自动QoS；卷复制；快照。磁盘通道带宽：系统支持384Gb/s磁盘通道带宽；支持快照数量：8192 支持LUN数量：16384
产品电源：AC 100-120V，750W；AC 200-240V，1000W
产品简介：浪潮 AS5600，高级功能：同步/异步远程复制功能；MAID绿色节能技术；存储高可用功能；存储高可用功能；自动分层；自动QoS；卷复制；快照。
浪潮AS5600热门行情行情|08-11行情|08-11行情|08-01行情|08-01行情|07-21行情|07-21行情|06-14行情|05-04行情|01-13行情|12-29
精彩提问标题作者回复天极网友1天极网友1天极网友1天极网友1天极网友1天极网友1天极网友1天极网友1
同品牌最热产品
热门链接：
接下来您可以
磁盘阵列新品推荐
磁盘阵列品牌排行
浪潮是中国领先的云计算整体解决方案供应商，已经形成涵盖IaaS、PaaS、SaaS三个层面的整体解决方案服务能力，凭借浪潮高端服务器、海量存储、... []
客服电话：400-860-0011800-860-0011800-860-6708
官方网站：
商家促销信息
免责声明：此页面（本网站）所显示的维修商主体资格、经营资质、报价、售后服务等承诺、以及所发布的商务信息等内容的真实性、准确性和合法性由发布维修商负责，不代表天极网观点，天极网亦对此不作任何承诺与保证，天极网所提供（本站显示）的信息资料仅作为市场资讯供用户参考。页面上带有”官方授权”图标的为官方授权维修点，维修商提交了官方授权书，带有“官网认证”图标的为官网认证维修点。天极网建议您选择同城具有相当资质的维修商当面交易，不要先直接打款给维修商，以降低自身风险。网络用户依其意志自主选择维修主体、维修物品，并自行承担后续风险，本站不承担任何法律责任。
|||||||||Copyright (C) 1999-, All Rights Reserved 版权所有 天极网络京公网安备84号浪潮AS520N参数
声明：仅供参考，以当地实际销售信息为准
最大存储容量：304TB
单机磁盘数量：暂无数据
处理器：暂无数据
高速缓存：最低配置8GB，最大可达到3....
最大存储容量
最低配置8GB，最大可达到32GB
外接主机通道
标配2个千兆网口，并支持扩展，最大可提供6个千兆网口
RAID 0，1，5，6等
控制器：单控制器
主机规格：3U16盘位
容量配置：4T，企业级SATA，硬盘3块，每套系统可提供最大裸容量≥304TB，支持扩展4U60盘位的高密度扩展柜
同一阵列同时支持SAS盘和SATA磁盘，且支持不同容量磁盘混插混插；支持图形化管理软件，可以进行资源占用、磁盘掉盘等系统状态监控；支持系统恢复，可以恢复到出厂状态；支持用户管理和访问控制，支持LDAP、ADS（Active Directory Service）域、NIS认证；供基于Web 的发现、监控、报告、配置和调整的存储管理软件；提供基于向导的初始化配置；支持Rsync协议进行数据备份和同步 ；能够实现数据的安全保护及快速恢复，提供启动时磁盘顺序加电功能，支持硬盘热插拔、磁盘漫游以及与外接UPS联动，防止数据损失；支持热插拔、双冗余，支持硬件监控和故障预警，支持邮件报警功能
>> PART:DetailVer3/Part/Detail/AdZPlusGoods >>> -->浪潮AS520G( LANGCHAO AS520G )
浪潮AS520G
参考价格：￥2000000
商家报价：￥2000000至￥2000000
高速缓存容量（MB）：每控制器8GB缓存，可升级至48GB
接口：SAS、NL SAS
RAID支持：0，1，5，6，10，50，60
主机通道：4个/8个千兆和4个8Gb FC 8个8Gb FC和8个千兆 12个8Gb FC和4个千兆 8个8Gb FC和12个千兆 2/4个万兆 16个FC
其他参数：控制器：冗余多控制器；硬盘数量：支持550块硬盘；扩展接口：6个SAS宽端口；扩展柜：3U16；高级功能：支持CIFS、NFS、FTP等NAS存储功能；LUN在线扩容；主机接口聚合；多路径冗余；卷复制；镜像；快照
工作温度：5-35℃
产品简介：浪潮 AS520G，控制器：冗余多控制器；硬盘数量：支持550块硬盘；扩展接口：6个SAS宽端口；扩展柜：3U16；高级功能：支持CIFS、NFS、FTP等NAS存储功能；LUN在线扩容；主机接口聚合；多路径冗余；卷复制；镜像；快照。
浪潮AS520G热门行情行情|08-11行情|08-11行情|08-01行情|08-01行情|07-21行情|07-21行情|06-14行情|05-04行情|01-13行情|12-29
精彩提问标题作者回复天极网友1天极网友1天极网友1天极网友1天极网友1天极网友1天极网友1天极网友1
同品牌最热产品
热门链接：
接下来您可以
磁盘阵列新品推荐
磁盘阵列品牌排行
浪潮是中国领先的云计算整体解决方案供应商，已经形成涵盖IaaS、PaaS、SaaS三个层面的整体解决方案服务能力，凭借浪潮高端服务器、海量存储、... []
客服电话：400-860-0011800-860-0011800-860-6708
官方网站：
商家促销信息
免责声明：此页面（本网站）所显示的维修商主体资格、经营资质、报价、售后服务等承诺、以及所发布的商务信息等内容的真实性、准确性和合法性由发布维修商负责，不代表天极网观点，天极网亦对此不作任何承诺与保证，天极网所提供（本站显示）的信息资料仅作为市场资讯供用户参考。页面上带有”官方授权”图标的为官方授权维修点，维修商提交了官方授权书，带有“官网认证”图标的为官网认证维修点。天极网建议您选择同城具有相当资质的维修商当面交易，不要先直接打款给维修商，以降低自身风险。网络用户依其意志自主选择维修主体、维修物品，并自行承担后续风险，本站不承担任何法律责任。
|||||||||Copyright (C) 1999-, All Rights Reserved 版权所有 天极网络京公网安备84号DS-AS82012D-海康威视磁盘阵列DS-AS82012D-杭州凯勒电子科技有限公司
<img id="zhantai_logo" src=/1/750.jpg alt=杭州凯勒电子科技有限公司 onload="120<=this.width?this.width=120:this.90
杭州凯勒电子科技有限公司
主营产品： 海康摄像机,海康录像机,大华摄像机,大华录像机,三星摄像机,弱电施工单位,杭州综合布线,小区监控维保
您现在的位置： &>>>&&&&DS-AS82012D海康威视磁盘阵列DS-AS82012D
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杭州市登云路428号
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DS-AS82012D海康威视磁盘阵列DS-AS82012D
产品型号：
DS-AS82012D
产品参考价：
厂商性质：
所 在 地：
更新时间：
浏览次数：
【简单介绍】
DS-AS82系列是海康推出的高可靠双控制器架构海量数据高端存储产品，高密机箱设计，4U机箱可支持24、60块硬盘，同时可级联扩展柜，单套系统最大可支持120块硬盘。该产品还提供高性能高可靠存储应用，支持高并发读写需求，支持控制器故障接管，可应用于大型数据中心建设、大型视频监控项目。
【详细说明】
海康威视磁盘阵列DS-AS82012D性能&&&&&&&&视频（2Mbps）&&&&& 256路（录像+回放）视频输入与输出&&&&录像+回放&&&&&& 240路2Mbps（480Mbps网络带宽）控制器&&&&处理器&&&& 双控制器（64位多核处理器）高速缓存&&&&&&&& 4GB/控制器（可扩展至16G）存储&&&&&&&&磁盘数量&&&&&&&& 12最大磁盘数&&&& 252磁盘接口及容量&&&& SAS/1TB、2TB、3TB、4TB（SSD可选）热插拔硬盘&&&& 支持RAID级别&&&&&&& RAID0、1、3、5、6、10、50、JBOD、Hot-Spare 存储管理&&&&&&&&磁盘管理&&&&&&&& 磁盘检测预警及修复逻辑卷管理&&&& NAS卷、iSCSI卷管理数据保护&&&&&&&& WORM防篡改、系统信息实时备份、卷克隆设备维管&&&&&&&&管理方式&&&&&&&& 基于Web的GUI，串口CLI，支持多设备统一管理报警方式&&&&&&&& 声、光、email、页面日志下载&&&&&&&& U盘自动下载、登陆网页本地保存网络管理&&&&&&&&网络协议&&&&&&&& iSCSI / NFS / CIFS / FTP / HTTP / AFP外部接口&&&&&&&&数据接口&&&&&&&& 每控制器4个千兆以太网口（可扩展至8个），可扩展2个万兆以太网口和4个8Gb FC口管理接口&&&&&&&& 每控制器1个千兆以太网口SAS扩展口&&&&& 支持COM接口&&&&&&& 每控制器2个，1个用于超级终端，1个用于外接UPSUSB接口 每控制器2个其他&&&&&&&&电源&&&&&&&& 冗余电源（1+1）功耗（含盘）&&&&&&&& 工作功耗：≤265W；额定功耗：≤595W环境温度&&&&&&&& 工作：5℃～40℃ 储藏：-20℃～70℃环境湿度&&&&&&&& 工作：20%～80%RH（无结冰、无凝露）& 储藏：5%～90%RH（无结冰、无凝露）机箱&&&&&&&& 19英寸2U标准机箱尺寸&&&&&&&& 486mm（宽）x87mm（高）x 570mm（深）重量（不含盘）&&&& ≤20Kg
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扫一扫访问手机商铺CreateFile function
Creates or opens a file or I/O device. The most commonly used I/O devices are as follows: file, file
stream, directory, physical disk, volume, console buffer, tape drive, communications resource, mailslot, and
pipe. The function returns a handle that can be used to access the file or device for various types of
I/O depending on the file or device and the flags and attributes specified.
To perform this operation as a transacted operation, which results in a handle that can be used for transacted
I/O, use the
HANDLE WINAPI CreateFile(
lpFileName,
dwDesiredAccess,
dwShareMode,
_In_opt_ LPSECURITY_ATTRIBUTES lpSecurityAttributes,
dwCreationDisposition,
dwFlagsAndAttributes,
_In_opt_ HANDLE
hTemplateFile
Parameters
lpFileName [in]
The name of the file or device to be created or opened. You may use either forward slashes (/) or backslashes (\) in this name.
In the ANSI version of this function, the name is limited to MAX_PATH characters.
To extend this limit to 32,767 wide characters, call the Unicode version of the function and prepend
"\\?\" to the path. For more information, see
For information on special device names, see
To create a file stream, specify the name of the file, a colon, and then the name of the stream. For more
information, see .
Starting with Windows 10, version 1607, for the unicode version of this function (CreateFileW), you can opt-in to remove the MAX_PATH limitation without prepending "\\?\". See the "Maximum Path Length Limitation" section of
for details.
dwDesiredAccess [in]
The requested access to the file or device, which can be summarized as read, write, both or neither zero).
The most commonly used values are GENERIC_READ,
GENERIC_WRITE, or both
(GENERIC_READ | GENERIC_WRITE). For more information, see
If this parameter is zero, the application can query certain metadata such as file, directory, or device
attributes without accessing that file or device, even if GENERIC_READ access would
have been denied.
You cannot request an access mode that conflicts with the sharing mode that is specified by the
dwShareMode parameter in an open request that already has an open handle.
For more information, see the Remarks section of this topic and
dwShareMode [in]
The requested sharing mode of the file or device, which can be read, write, both, delete, all of these, or
none (refer to the following table). Access requests to attributes or extended attributes are not affected by
this flag.
If this parameter is zero and CreateFile succeeds, the
file or device cannot be shared and cannot be opened again until the handle to the file or device is closed.
For more information, see the Remarks section.
You cannot request a sharing mode that conflicts with the access mode that is specified in an existing
request that has an open handle. CreateFile would fail and
function would return
ERROR_SHARING_VIOLATION.
To enable a process to share a file or device while another process has the file or device open, use a
compatible combination of one or more of the following values. For more information about valid combinations of
this parameter with the dwDesiredAccess parameter, see
The sharing options for each open handle remain in effect until that handle is closed, regardless of
process context.
ValueMeaning
Prevents other processes from opening a file or device if they request delete, read, or write access.
FILE_SHARE_DELETE
Enables subsequent open operations on a file or device to request delete access.
Otherwise, other processes cannot open the file or device if they request delete access.
If this flag is not specified, but the file or device has been opened for delete access, the function
Delete access allows both delete and rename operations.
FILE_SHARE_READ
Enables subsequent open operations on a file or device to request read access.
Otherwise, other processes cannot open the file or device if they request read access.
If this flag is not specified, but the file or device has been opened for read access, the function
FILE_SHARE_WRITE
Enables subsequent open operations on a file or device to request write access.
Otherwise, other processes cannot open the file or device if they request write access.
If this flag is not specified, but the file or device has been opened for write access or has a file mapping
with write access, the function fails.
lpSecurityAttributes [in, optional]
A pointer to a
structure that contains two separate but related data members: an optional security descriptor, and a Boolean
value that determines whether the returned handle can be inherited by child processes.
This parameter can be NULL.
If this parameter is NULL, the handle returned by
CreateFile cannot be inherited by any child processes the
application may create and the file or device associated with the returned handle gets a default security
descriptor.
The lpSecurityDescriptor member of the structure specifies a
for a file or device. If
this member is NULL, the file or device associated with the returned handle is
assigned a default security descriptor.
CreateFile ignores the
lpSecurityDescriptor member when opening an existing file or device, but continues
to use the bInheritHandle member.
The bInheritHandlemember of the structure specifies whether the returned handle
can be inherited.
For more information, see the Remarks section.
dwCreationDisposition [in]
An action to take on a file or device that exists or does not exist.
For devices other than files, this parameter is usually set to OPEN_EXISTING.
For more information, see the Remarks section.
This parameter must be one of the following values, which cannot be combined:
ValueMeaning
CREATE_ALWAYS
Creates a new file, always.
If the specified file exists and is writable, the function overwrites the file, the function succeeds, and
last-error code is set to ERROR_ALREADY_EXISTS (183).
If the specified file does not exist and is a valid path, a new file is created, the function succeeds, and
the last-error code is set to zero.
For more information, see the Remarks section of this topic.
CREATE_NEW
Creates a new file, only if it does not already exist.
If the specified file exists, the function fails and the last-error code is set to
ERROR_FILE_EXISTS (80).
If the specified file does not exist and is a valid path to a writable location, a new file is created.
OPEN_ALWAYS
Opens a file, always.
If the specified file exists, the function succeeds and the last-error code is set to
ERROR_ALREADY_EXISTS (183).
If the specified file does not exist and is a valid path to a writable location, the function creates a
file and the last-error code is set to zero.
OPEN_EXISTING
Opens a file or device, only if it exists.
If the specified file or device does not exist, the function fails and the last-error code is set to
ERROR_FILE_NOT_FOUND (2).
For more information about devices, see the Remarks section.
TRUNCATE_EXISTING
Opens a file and truncates it so that its size is zero bytes, only if it exists.
If the specified file does not exist, the function fails and the last-error code is set to
ERROR_FILE_NOT_FOUND (2).
The calling process must open the file with the GENERIC_WRITE bit set as part of
the dwDesiredAccess parameter.
dwFlagsAndAttributes [in]
The file or device attributes and flags, FILE_ATTRIBUTE_NORMAL being the most
common default value for files.
This parameter can include any combination of the available file attributes
(FILE_ATTRIBUTE_*). All other file attributes override
FILE_ATTRIBUTE_NORMAL.
This parameter can also contain combinations of flags (FILE_FLAG_*) for control of
file or device caching behavior, access modes, and other special-purpose flags. These combine with any
FILE_ATTRIBUTE_* values.
This parameter can also contain Security Quality of Service (SQOS) information by specifying the
SECURITY_SQOS_PRESENT flag. Additional SQOS-related flags information is presented in
the table following the attributes and flags tables.
When CreateFile opens an existing file, it generally
combines the file flags with the file attributes of the existing file, and ignores any file attributes supplied
as part of dwFlagsAndAttributes. Special cases are detailed in
Some of the following file attributes and flags may only apply to files and not necessarily all other types
of devices that CreateFile can open. For additional
information, see the Remarks section of this topic and
For more advanced access to file attributes, see
. For a complete list
of all file attributes with their values and descriptions, see
AttributeMeaning
FILE_ATTRIBUTE_ARCHIVE
The file should be archived. Applications use this attribute to mark files for backup or removal.
FILE_ATTRIBUTE_ENCRYPTED
The file or directory is encrypted. For a file, this means that all data in the file is encrypted. For a
directory, this means that encryption is the default for newly created files and subdirectories. For more
information, see .
This flag has no effect if FILE_ATTRIBUTE_SYSTEM is also specified.
This flag is not supported on Home, Home Premium, Starter, or ARM editions of Windows.
FILE_ATTRIBUTE_HIDDEN
The file is hidden. Do not include it in an ordinary directory listing.
FILE_ATTRIBUTE_NORMAL
128 (0x80)
The file does not have other attributes set. This attribute is valid only if used alone.
FILE_ATTRIBUTE_OFFLINE
The data of a file is not immediately available. This attribute indicates that file data is physically
moved to offline storage. This attribute is used by Remote Storage, the hierarchical storage management
software. Applications should not arbitrarily change this attribute.
FILE_ATTRIBUTE_READONLY
The file is read only. Applications can read the file, but cannot write to or delete it.
FILE_ATTRIBUTE_SYSTEM
The file is part of or used exclusively by an operating system.
FILE_ATTRIBUTE_TEMPORARY
256 (0x100)
The file is being used for temporary storage.
For more information, see the
section of this
FlagMeaning
FILE_FLAG_BACKUP_SEMANTICS
The file is being opened or created for a backup or restore operation. The system ensures that the calling
process overrides file security checks when the process has SE_BACKUP_NAME and
SE_RESTORE_NAME privileges. For more information, see
You must set this flag to obtain a handle to a directory. A directory handle can be passed to some
functions instead of a file handle. For more information, see the Remarks section.
FILE_FLAG_DELETE_ON_CLOSE
The file is to be deleted immediately after all of its handles are closed, which includes the specified
handle and any other open or duplicated handles.
If there are existing open handles to a file, the call fails unless they were all opened with the
FILE_SHARE_DELETE share mode.
Subsequent open requests for the file fail, unless the FILE_SHARE_DELETE share
mode is specified.
FILE_FLAG_NO_BUFFERING
The file or device is being opened with no system caching for data reads and writes. This flag does not
affect hard disk caching or memory mapped files.
There are strict requirements for successfully working with files opened with
CreateFile using the
FILE_FLAG_NO_BUFFERING flag, for details see
FILE_FLAG_OPEN_NO_RECALL
The file data is requested, but it should continue to be located in remote storage. It should not be
transported back to local storage. This flag is for use by remote storage systems.
FILE_FLAG_OPEN_REPARSE_POINT
processing will not
CreateFile will attempt to open the reparse
point. When a file is opened, a file handle is returned, whether or not the filter that controls the reparse
point is operational.
This flag cannot be used with the CREATE_ALWAYS flag.
If the file is not a reparse point, then this flag is ignored.
For more information, see the Remarks section.
FILE_FLAG_OVERLAPPED
The file or device is being opened or created for asynchronous I/O.
When subsequent I/O operations are completed on this handle, the event specified in the
structure will be set to the
signaled state.
If this flag is specified, the file can be used for simultaneous read and write operations.
If this flag is not specified, then I/O operations are serialized, even if the calls to the read and write
functions specify an
structure.
For information about considerations when using a file handle created with this flag, see the
section of this topic.
FILE_FLAG_POSIX_SEMANTICS
Access will occur according to POSIX rules. This includes allowing multiple files with names, differing
only in case, for file systems that support that naming. Use care when using this option, because files
created with this flag may not be accessible by applications that are written for MS-DOS or 16-bit
FILE_FLAG_RANDOM_ACCESS
Access is intended to be random. The system can use this as a hint to optimize file caching.
This flag has no effect if the file system does not support cached I/O and
FILE_FLAG_NO_BUFFERING.
For more information, see the
section of this
FILE_FLAG_SESSION_AWARE
The file or device is being opened with session awareness. If this flag is not specified, then per-session
devices (such as a device using RemoteFX USB Redirection) cannot be opened by processes running in session 0.
This flag has no effect for callers not in session 0. This flag is supported only on server editions of
Windows Server 2008 R2 and Windows Server 2008:
This flag is not supported before Windows Server 2012.
FILE_FLAG_SEQUENTIAL_SCAN
Access is intended to be sequential from beginning to end. The system can use this as a hint to optimize
file caching.
This flag should not be used if read-behind (that is, reverse scans) will be used.
This flag has no effect if the file system does not support cached I/O and
FILE_FLAG_NO_BUFFERING.
For more information, see the
section of this
FILE_FLAG_WRITE_THROUGH
Write operations will not go through any intermediate cache, they will go directly to disk.
For additional information, see the
section of this
The dwFlagsAndAttributesparameter can also specify SQOS information. For more
information, see
. When the
calling application specifies the SECURITY_SQOS_PRESENT flag as part of
dwFlagsAndAttributes, it can also contain one or more of the following values.
Security flagMeaning
SECURITY_ANONYMOUS
Impersonates a client at the Anonymous impersonation level.
SECURITY_CONTEXT_TRACKING
The security tracking mode is dynamic. If this flag is not specified, the security tracking mode is
SECURITY_DELEGATION
Impersonates a client at the Delegation impersonation level.
SECURITY_EFFECTIVE_ONLY
Only the enabled aspects of the client's security context are available to the server. If you do not
specify this flag, all aspects of the client's security context are available.
This allows the client to limit the groups and privileges that a server can use while impersonating the
SECURITY_IDENTIFICATION
Impersonates a client at the Identification impersonation level.
SECURITY_IMPERSONATION
Impersonate a client at the impersonation level. This is the default behavior if no other flags are
specified along with the SECURITY_SQOS_PRESENT flag.
hTemplateFile [in, optional]
A valid handle to a template file with the GENERIC_READ access right. The template
file supplies file attributes and extended attributes for the file that is being created.
This parameter can be NULL.
When opening an existing file, CreateFile ignores this
parameter.
When opening a new encrypted file, the file inherits the discretionary access control list from its parent
directory. For additional information, see
Return value
If the function succeeds, the return value is an open handle to the specified file, device, named pipe, or
mail slot.
If the function fails, the return value is INVALID_HANDLE_VALUE. To get extended
error information, call .
CreateFile was originally developed specifically for file
interaction but has since been expanded and enhanced to include most other types of I/O devices and mechanisms
available to Windows developers. This section attempts to cover the varied issues developers may experience when
using CreateFile in different contexts and with different I/O
types. The text attempts to use the word file only when referring specifically to data stored in an
actual file on a file system. However, some uses of file may be referring more generally to an I/O
object that supports file-like mechanisms. This liberal use of the term file is particularly
prevalent in constant names and parameter names because of the previously mentioned historical reasons.
When an application is finished using the object handle returned by
CreateFile, use the
function to close the handle. This not only
frees up system resources, but can have wider influence on things like sharing the file or device and committing
data to disk. Specifics are noted within this topic as appropriate.
Windows Server 2003 and Windows XP:
A sharing violation occurs if an attempt is made to open a file or directory for deletion on a remote
computer when the value of the dwDesiredAccess parameter is the
DELETE access flag (0x) OR'ed with any other access flag, and the remote file
or directory has not been opened with FILE_SHARE_DELETE. To avoid the sharing violation
in this scenario, open the remote file or directory with the DELETE access right only,
without first opening the file or
directory for deletion.
Some file systems, such as the NTFS file system, support compression or encryption for individual files and
directories. On volumes that have a mounted file system with this support, a new file inherits the compression
and encryption attributes of its directory.
You cannot use CreateFile to control compression,
decompression, or decryption on a file or directory. For more information, see
Windows Server 2003 and Windows XP:
For backward compatibility purposes, CreateFile does
not apply inheritance rules when you specify a security descriptor in
lpSecurityAttributes. To support inheritance, functions that later query the security
descriptor of this file may heuristically determine and report that inheritance is in effect. For more
information, see
As stated previously, if the lpSecurityAttributes parameter is
NULL, the handle returned by
CreateFile cannot be inherited by any child processes your
application may create. The following information regarding this parameter also applies:
If the bInheritHandle member variable is not FALSE,
which is any nonzero value, then the handle can be inherited. Therefore it is critical this structure member be
properly initialized to FALSE if you do not intend the handle to be inheritable.
The access control lists (ACL) in the default security descriptor for a file or directory are inherited
from its parent directory.
The target file system must support security on files and directories for the
lpSecurityDescriptor member to have an effect on them, which can be determined by
In Windows 8 and Windows Server 2012, this function is supported by the following technologies.
TechnologySupported
Server Message Block (SMB) 3.0 protocol
SMB 3.0 Transparent Failover (TFO)
See remarks
SMB 3.0 with Scale-out File Shares (SO)
See remarks
Cluster Shared Volume File System (CsvFS)
Resilient File System (ReFS)
Note that CreateFile with supersede disposition will fail if performed on a file where there is already an open alternate data stream.
Symbolic Link Behavior
If the call to this function creates a file, there is no change in behavior. Also, consider the following
information regarding FILE_FLAG_OPEN_REPARSE_POINT:
If FILE_FLAG_OPEN_REPARSE_POINT is specified:
If an existing file is opened and it is a symbolic link, the handle returned is a handle to the
symbolic link.
If TRUNCATE_EXISTING or FILE_FLAG_DELETE_ON_CLOSE
are specified, the file affected is a symbolic link.
If FILE_FLAG_OPEN_REPARSE_POINT is not specified:
If an existing file is opened and it is a symbolic link, the handle returned is a handle to the
If CREATE_ALWAYS, TRUNCATE_EXISTING, or
FILE_FLAG_DELETE_ON_CLOSE are specified, the file affected is the target.
Caching Behavior
Several of the possible values for the dwFlagsAndAttributes parameter are used by
CreateFile to control or affect how the data associated
with the handle is cached by the system. They are:
FILE_FLAG_NO_BUFFERING
FILE_FLAG_RANDOM_ACCESS
FILE_FLAG_SEQUENTIAL_SCAN
FILE_FLAG_WRITE_THROUGH
FILE_ATTRIBUTE_TEMPORARY
If none of these flags is specified, the system uses a default general-purpose caching scheme. Otherwise, the
system caching behaves as specified for each flag.
Some of these flags should not be combined. For instance, combining
FILE_FLAG_RANDOM_ACCESS with FILE_FLAG_SEQUENTIAL_SCAN is
self-defeating.
Specifying the FILE_FLAG_SEQUENTIAL_SCAN flag can increase performance for
applications that read large files using sequential access. Performance gains can be even more noticeable for
applications that read large files mostly sequentially, but occasionally skip forward over small ranges of
bytes. If an application moves the file pointer for random access, optimum caching performance most likely will
not occur. However, correct operation is still guaranteed.
The flags FILE_FLAG_WRITE_THROUGH and
FILE_FLAG_NO_BUFFERING are independent and may be combined.
If FILE_FLAG_WRITE_THROUGH is used but
FILE_FLAG_NO_BUFFERING is not also specified, so that system caching is in effect,
then the data is written to the system cache but is flushed to disk without delay.
If FILE_FLAG_WRITE_THROUGH and FILE_FLAG_NO_BUFFERING are
both specified, so that system caching is not in effect, then the data is immediately flushed to disk without
going through the Windows system cache. The operating system also requests a write-through of the hard disk's
local hardware cache to persistent media.
Not all hard disk hardware supports this write-through capability.
Proper use of the FILE_FLAG_NO_BUFFERING flag requires special application
considerations. For more information, see
A write-through request via FILE_FLAG_WRITE_THROUGH also causes NTFS to flush any
metadata changes, such as a time stamp update or a rename operation, that result from processing the request.
For this reason, the FILE_FLAG_WRITE_THROUGH flag is often used with the
FILE_FLAG_NO_BUFFERING flag as a replacement for calling the
function after each write, which can
cause unnecessary performance penalties. Using these flags together avoids those penalties. For general
information about the caching of files and metadata, see
When FILE_FLAG_NO_BUFFERING is combined with
FILE_FLAG_OVERLAPPED, the flags give maximum asynchronous performance, because the I/O
does not rely on the synchronous operations of the memory manager. However, some I/O operations take more time,
because data is not being held in the cache. Also, the file metadata may still be cached (for example, when
creating an empty file). To ensure that the metadata is flushed to disk, use the
Specifying the FILE_ATTRIBUTE_TEMPORARY attribute causes file systems to avoid
writing data back to mass storage if sufficient cache memory is available, because an application deletes a
temporary file after a handle is closed. In that case, the system can entirely avoid writing the data. Although
it does not directly control data caching in the same way as the previously mentioned flags, the
FILE_ATTRIBUTE_TEMPORARY attribute does tell the system to hold as much as possible in
the system cache without writing and therefore may be of concern for certain applications.
If you rename or delete a file and then restore it shortly afterward, the system searches the cache for file
information to restore. Cached information includes its short/long name pair and creation time.
If you call CreateFile on a file that is pending deletion
as a result of a previous call to , the function
fails. The operating system delays file deletion until all handles to the file are closed.
ERROR_ACCESS_DENIED.
The dwDesiredAccess parameter can be zero, allowing the application to query file
attributes without accessing the file if the application is running with adequate security settings. This is
useful to test for the existence of a file without opening it for read and/or write access, or to obtain other
statistics about the file or directory. See
If CREATE_ALWAYS and FILE_ATTRIBUTE_NORMAL are
specified, CreateFile fails and sets the last error to
ERROR_ACCESS_DENIED if the file exists and has the
FILE_ATTRIBUTE_HIDDEN or FILE_ATTRIBUTE_SYSTEM attribute.
To avoid the error, specify the same attributes as the existing file.
When an application creates a file across a network, it is better to use
GENERIC_READ | GENERIC_WRITE for
dwDesiredAccess than to use GENERIC_WRITE alone. The
resulting code is faster, because the redirector can use the cache manager and send fewer SMBs with more data.
This combination also avoids an issue where writing to a file across a network can occasionally return
ERROR_ACCESS_DENIED.
For more information, see
Synchronous and Asynchronous I/O Handles
CreateFile provides for creating a file or device handle
that is either synchronous or asynchronous. A synchronous handle behaves such that I/O function calls using that
handle are blocked until they complete, while an asynchronous file handle makes it possible for the system to
return immediately from I/O function calls, whether they completed the I/O operation or not. As stated
previously, this synchronous versus asynchronous behavior is determined by specifying
FILE_FLAG_OVERLAPPED within the dwFlagsAndAttributes
parameter. There are several complexities and potential pitfalls when using asynchronous I/O; for more
information, see
File Streams
On NTFS file systems, you can use CreateFile to create
separate streams within a file. For more information, see
Directories
An application cannot create a directory by using
CreateFile, therefore only the
OPEN_EXISTING value is valid for
dwCreationDisposition for this use case. To create a directory, the application must
To open a directory using CreateFile, specify the
FILE_FLAG_BACKUP_SEMANTICS flag as part of
dwFlagsAndAttributes. Appropriate security checks still apply when this flag is used
without SE_BACKUP_NAME and SE_RESTORE_NAME privileges.
When using CreateFile to open a directory during
defragmentation of a FAT or FAT32 file system volume, do not specify the
MAXIMUM_ALLOWED access right. Access to the directory is denied if this is done.
Specify the GENERIC_READ access right instead.
For more information, see
Physical Disks and Volumes
Direct access to the disk or to a volume is restricted. For more information, see
"Changes to the file system and to the storage stack to restrict direct disk access and direct volume access in Windows Vista and in Windows Server 2008"
in the Help and Support Knowledge Base at
Windows Server 2003 and Windows XP:
Direct access to the disk or to a volume is not restricted in this manner.
You can use the CreateFile function to open a physical
disk drive or a volume, which returns a direct access storage device (DASD) handle that can be used with the
function. This enables you to access
the disk or volume directly, for example such disk metadata as the partition table. However, this type of access
also exposes the disk drive or volume to potential data loss, because an incorrect write to a disk using this
mechanism could make its contents inaccessible to the operating system. To ensure data integrity, be sure to
become familiar with DeviceIoControl and how other
APIs behave differently with a direct access handle as opposed to a file system handle.
The following requirements must be met for such a call to succeed:
The caller must have administrative privileges. For more information, see
The dwCreationDisposition parameter must have the
OPEN_EXISTINGflag.
When opening a volume or floppy disk, the dwShareMode parameter must have the
FILE_SHARE_WRITEflag.
The dwDesiredAccess parameter can be zero, allowing the application to query
device attributes without accessing a device. This is useful for an application to determine the size of a
floppy disk drive and the formats it supports without requiring a floppy disk in a drive, for instance. It can
also be used for reading statistics without requiring higher-level data read/write permission.
When opening a physical drive x:, the
lpFileName string should be the following form:
"\\.\PhysicalDriveX". Hard disk numbers
start at zero. The following table shows some examples of physical drive strings.
StringMeaning
"\\.\PhysicalDrive0"Opens the first physical drive.
"\\.\PhysicalDrive2"Opens the third physical drive.
To obtain the physical drive identifier for a volume, open a handle to the volume and call the
function with
This control code returns the disk number and offset for each of the volume's a volume can
span multiple physical disks.
For an example of opening a physical drive, see
When opening a volume or removable media drive (for example, a floppy disk drive or flash memory thumb drive),
the lpFileName string should be the following form:
"\\.\X:". Do not use a trailing backslash
(\), which indicates the root directory of a drive. The following table shows some examples of drive strings.
StringMeaning
"\\.\A:"Opens floppy disk drive A.
"\\.\C:"Opens the C: volume.
"\\.\C:\"Opens the file system of the C: volume.
You can also open a volume by referring to its volume name. For more information, see
A volume contains one or more mounted file systems. Volume handles can be opened as noncached at the
discretion of the particular file system, even when the noncached option is not specified in
CreateFile. You should assume that all Microsoft file
systems open volume handles as noncached. The restrictions on noncached I/O for files also apply to volumes.
A file system may or may not require buffer alignment even though the data is noncached. However, if the
noncached option is specified when opening a volume, buffer alignment is enforced regardless of the file system
on the volume. It is recommended on all file systems that you open volume handles as noncached, and follow the
noncached I/O restrictions.
To read or write to the last few sectors of the volume, you must call
and specify
. This signals
the file system driver not to perform any I/O boundary checks on partition read or write calls. Instead,
boundary checks are performed by the device driver.
Changer Device
The IOCTL_CHANGER_* control codes for
accept a handle to a changer device.
To open a changer device, use a file name of the following form:
"\\.\Changerx" where
x is a number that indicates which device to open, starting with zero. To open
changer device zero in an application that is written in C or C++, use the following file name:
"\\\\.\\Changer0".
Tape Drives
You can open tape drives by using a file name of the following form:
"\\.\TAPEx" where
x is a number that indicates which drive to open, starting with tape drive zero. To
open tape drive zero in an application that is written in C or C++, use the following file name:
"\\\\.\\TAPE0".
For more information, see .
Communications Resources
The CreateFile function can create a handle to a
communications resource, such as the serial port COM1. For communications resources,
the dwCreationDisposition parameter must be
OPEN_EXISTING, the dwShareMode parameter must be zero
(exclusive access), and the hTemplateFile parameter must be
NULL. Read, write, or read/write access can be specified, and the handle can be opened
for overlapped I/O.
To specify a COM port number greater than 9, use the following syntax:
"\\.\COM10". This syntax works for all port numbers and hardware that
allows COM port numbers to be specified.
For more information about communications, see
The CreateFile function can create a handle to console
input (CONIN$). If the process has an open handle to it as a result of inheritance or
duplication, it can also create a handle to the active screen buffer (CONOUT$). The
calling process must be attached to an inherited console or one allocated by the
function. For console handles, set the
CreateFile parameters as follows.
ParametersValue
lpFileName
Use the CONIN$ value to specify console input.
Use the CONOUT$ value to specify console output.
CONIN$ gets a handle to the console input buffer, even if the
function redirects the standard input
handle. To get the standard input handle, use the
CONOUT$ gets a handle to the active screen buffer, even if
redirects the standard output handle. To
get the standard output handle, use .
dwDesiredAccess
GENERIC_READ | GENERIC_WRITE is preferred, but either one can
limit access.
dwShareMode
When opening CONIN$, specify
FILE_SHARE_READ. When opening CONOUT$, specify
FILE_SHARE_WRITE.
If the calling process inherits the console, or if a child process should be able to access the console,
this parameter must be FILE_SHARE_READ | FILE_SHARE_WRITE.
lpSecurityAttributes
If you want the console to be inherited, the bInheritHandle member of the
must be TRUE.
dwCreationDisposition
You should specify OPEN_EXISTING when using
CreateFile to open the console.
dwFlagsAndAttributes
hTemplateFile
The following table shows various settings of dwDesiredAccess and
lpFileName.
lpFileNamedwDesiredAccessResult
"CON"GENERIC_READOpens console for input.
"CON"GENERIC_WRITEOpens console for output.
"CON"GENERIC_READ | GENERIC_WRITECauses CreateFile
ERROR_FILE_NOT_FOUND.
If CreateFileopens the client end of a mailslot, the
function returns INVALID_HANDLE_VALUE if the mailslot client attempts to open a local
mailslot before the mailslot server has created it with the
For more information, see .
If CreateFile opens the client end of a named pipe, the
function uses any instance of the named pipe that is in the listening state. The opening process can duplicate
the handle as many times as required, but after it is opened, the named pipe instance cannot be opened by
another client. The access that is specified when a pipe is opened must be compatible with the access that is
specified in the dwOpenModeparameter of the
function was not
successfully called on the server prior to this operation, a pipe will not exist and
CreateFile will fail with
ERROR_FILE_NOT_FOUND.
If there is at least one active pipe instance but there are no available listener pipes on the server, which
means all pipe instances are currently connected,
CreateFile fails with
ERROR_PIPE_BUSY.
For more information, see .
Example file operations are shown in the following topics:
Physical device I/O is demonstrated in the following topics:
An example using named pipes is located at
Working with a mailslot is shown in
A tape backup code snippet can found at
Requirements
Minimum supported client
Windows XP [desktop apps only]
Minimum supported server
Windows Server 2003 [desktop apps only]
FileAPI.h (include Windows.h);
WinBase.h on Windows Server 2008 R2, Windows 7, Windows Server 2008, Windows Vista, Windows Server 2003 and Windows XP (include Windows.h)
Kernel32.lib
Kernel32.dll
Unicode and ANSI names
CreateFileW (Unicode) and CreateFileA (ANSI)
Overview Topics
IN THIS ARTICLE
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