🚀 go-pugleaf

In article <C19M1B.KHM@dscomsa.desy.de>, hallam@zeus02.desy.de 
(Phill Hallam-Baker) writes:
> |>"Non-DSA disk devices can read or write up to 65.535 bytes in a single
> |> request. DSA devices connected to an HSC50 can transfer up to 4 billion
> |> bytes in a single request. In all cases, the maximum size of the transfer
> |> is limited by the number of pages which can be faulted into the process's
> |> working set and then locked into memory."
> |>
> |>The relevant fields of the IRP were expanded to 32 bits during the V3 -> V4
> |>enhancements.
> 
> Read the device driver manual and look at the format of the QIO. The 16 bit
> length is hard coded in there.

Where are you looking, and in what "device driver manual"?  

The code in places like EXE$WRITE (often used as an FDT routine for handling
"generic" direct I/O requests) handles the P2 argument (transfer length in
bytes) as a longword.  It's saved in IRP$L_BCNT as a longword.  Many device
drivers return the transfer length in the second and third words of the IOSB,
as a longword.  

	--- Jamie Hanrahan, Kernel Mode Systems, San Diego CA
drivers, internals, networks, applications, and training for VMS and Windows NT
uucp 'g' protocol guru and release coordinator, VMSnet (DECUS uucp) W.G., and 
Chair, Programming and Internals Working Group, U.S. DECUS VMS Systems SIG 
Internet:  jeh@cmkrnl.com, or hanrahan@eisner.decus.org  Uucp: uunet!cmkrnl!jeh