user buffer question
in [Device Drivers]
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From: Kid on 5 Jul 2010 00:23 hi Can we use virtual memory or file mapping view buffer for device control and read / write ? How can we send large data more than gigabytes to USB device ? Thank for your teaching .
From: Don Burn on 5 Jul 2010 08:41 Why would you want to have a gigabyte buffer? USB (even USB 3.0) is not fast enough to warrant this type of buffering. Your approach would consume significant system resources so slow down the whole computer. If this is a commercial product please let us know what company so we can boycott the firm offering it. Don Burn (MVP, Windows DKD) Windows Filesystem and Driver Consulting Website: http://www.windrvr.com Blog: http://msmvps.com/blogs/WinDrvr > -----Original Message----- > From: Kid [mailto:Kid(a)discussions.microsoft.com] > Posted At: Monday, July 05, 2010 12:23 AM > Posted To: microsoft.public.development.device.drivers > Conversation: user buffer question > Subject: user buffer question > > hi > > Can we use virtual memory or file mapping view buffer for device control > and > read / write ? How can we send large data more than gigabytes to USB > device > ? > > Thank for your teaching . > > > __________ Information from ESET Smart Security, version of virus > signature > database 5251 (20100704) __________ > > The message was checked by ESET Smart Security. > > http://www.eset.com >
From: Kid on 6 Jul 2010 02:16 What is the max buffer size do you suggest ? "Don Burn" wrote: > Why would you want to have a gigabyte buffer? USB (even USB 3.0) is not > fast enough to warrant this type of buffering. Your approach would > consume significant system resources so slow down the whole computer. If > this is a commercial product please let us know what company so we can > boycott the firm offering it. > > > Don Burn (MVP, Windows DKD) > Windows Filesystem and Driver Consulting > Website: http://www.windrvr.com > Blog: http://msmvps.com/blogs/WinDrvr > > > > > -----Original Message----- > > From: Kid [mailto:Kid(a)discussions.microsoft.com] > > Posted At: Monday, July 05, 2010 12:23 AM > > Posted To: microsoft.public.development.device.drivers > > Conversation: user buffer question > > Subject: user buffer question > > > > hi > > > > Can we use virtual memory or file mapping view buffer for device control > > and > > read / write ? How can we send large data more than gigabytes to USB > > device > > ? > > > > Thank for your teaching . > > > > > > __________ Information from ESET Smart Security, version of virus > > signature > > database 5251 (20100704) __________ > > > > The message was checked by ESET Smart Security. > > > > http://www.eset.com > > > > . >
From: Tim Roberts on 7 Jul 2010 01:45 Kid <Kid(a)discussions.microsoft.com> wrote: > >What is the max buffer size do you suggest ? You need to do the math here. A gigabyte is going to take 20 or 25 seconds to transfer, so there's no performance benefit in doing it as one big transfer vs a whole bunch of smaller transfers. As long as the transfers are multiples of 512 bytes, the device will see it as one big transfer. -- Tim Roberts, timr(a)probo.com Providenza & Boekelheide, Inc.
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