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Groups > comp.lang.python > #24520
| From | "Adam" <adam@no_thanks.com> |
|---|---|
| Newsgroups | comp.lang.python, microsoft.public.windowsxp.general |
| Subject | Re: PySerial could not open port COM4: [Error 5] Access is denied - please help |
| Date | 2012-06-27 08:26 -0700 |
| Organization | A noiseless patient Spider |
| Message-ID | <jsf8nf$13d$1@dont-email.me> (permalink) |
| References | <jse17v$d5n$1@dont-email.me> <jse604$1cq$1@dont-email.me> <jseim6$tn7$1@dont-email.me> <jseu9c$sp3$1@dont-email.me> |
Cross-posted to 2 groups.
"Paul" <nospam@needed.com> wrote in message
news:jseu9c$sp3$1@dont-email.me...
> Adam wrote:
>> "John Nagle" <nagle@animats.com> wrote in message
>> news:jse604$1cq$1@dont-email.me...
>>> On 6/26/2012 9:12 PM, Adam wrote:
>>>> Host OS: Ubuntu 10.04 LTS
>>>> Guest OS: Windows XP Pro SP3
>>>>
>>>>
>>>> I am able to open port COM4 with Terminal emulator.
>>>>
>>>> So, what can cause PySerial to generate the following error ...
>>>>
>>>> C:\Wattcher>python wattcher.py
>>>> Traceback (most recent call last):
>>>> File "wattcher.py", line 56, in <module>
>>>> ser.open()
>>>> File "C:\Python25\Lib\site-packages\serial\serialwin32.py", line 56,
>>>> in
>>>> open
>>>> raise SerialException("could not open port %s: %s" %
>>>> (self.portstr,
>>>> ctypes.WinError()))
>>>> serial.serialutil.SerialException: could not open port COM4: [Error 5]
>>>> Access is denied.
>>> Are you trying to access serial ports from a virtual machine?
>>> Which virtual machine environment? Xen? VMware? QEmu? VirtualBox?
>>> I wouldn't expect that to work in most of those.
>>>
>>> What is "COM4", anyway? Few machines today actually have four
>>> serial ports. Is some device emulating a serial port?
>>>
>>> John Nagle
>>>
>>
>> Thanks, and yes, I am using VirtualBox. My laptop does not have a serial
>> port so
>> I use a USB-to-serial converter, which is assigned COM4.
>>
>
> Doesn't VirtualBox allow "remapping" serial ports ? I thought you
> could have COM 4 in the host OS, and make it COM 1 or COM 2 in
> the guest. Something like that.
>
> http://virtuatopia.com/images/6/60/Virtualbox_serial_port_settings.jpg
>
> Also, Windows (as a host), is notorious for stealing control of
> COM ports. Even Windows software, when you run it, would report
> "COM 4 is busy". Then, you have to track down *why* it's busy.
> Is it that FAX software you installed ? The GPS software
> that talks to your GPS serial interface ?
>
> In theory, the "Handle" program is supposed to identify what
> is keeping a COM port busy, but I don't get the desired
> results from it very often. You need to know the naming
> convention for virtual COM ports (COM4 via USB to serial, is
> more virtual than physical). That's what makes it harder
> to track down.
>
> These are some names for COM ports, in Windows. The last two entries,
> are my USB to serial adapters. VCP1 functions as COM3.
> VCP0 functions as COM4. The VCP part is what would be
> listed in "Handle" from Sysinternals. The \device\serial
> format, is more likely to be used with true "native"
> motherboard serial ports.
>
> \device\serial
>
> ups.exe pid: 1072 NT AUTHORITY\SYSTEM
> 98: File (---) \Device\VCP0
> hypertrm.exe pid: 3404 ComputerName\UserID (claims to use COM3)
> E0: File (---) \Device\VCP1
>
> You can download "Handle" and play with it here.
>
> http://technet.microsoft.com/en-us/sysinternals/bb896655
>
> Note that, in my Handle results, at the time I was running
> the Windows provided ups.exe to talk to my external UPS
> (uninterruptible power supply). So that's what that
> reference is. The "hypertrm" one, is me using the
> built-in Windows terminal software, to talk to COM3,
> to keep the port artificially busy for the purposes
> of testing.
>
> If things were working well in your case, you *might*
> see something of this form. If not, you'd instead
> see the name of the process that has "stolen" the
> com port.
>
> virtualbox.exe pid: 1234 ComputerName\UserID
> E0: File (---) \Device\VCP0
>
> HTH,
> Paul
Thanks (Guru Paul), I've been using the USB-to-serial converter successfully
without
enabling/remapping via VBox Settings=>Serial Ports (which are both "not"
enabled).
I can see the serial port COM4 under Device Manager though. So, maybe
enabling is
necessary when the host has "native" serial ports, which my laptop does not
have.
From the output generated by Handle.exe, here's the section for TeraTerm ...
------------------------------------------------------------------------------
ttermpro.exe pid: 596 VBOX_WINXPPRO\adam (claims to use COM4)
C: File (RW-) D:\downloads\Tera Term Pro\ttpro313
2C: Section \BaseNamedObjects\ttset_memfilemap
44: File (RW-)
C:\WINDOWS.0\WinSxS\x86_Microsoft.Windows.Common-Controls_6595b64144ccf1df_6.0.2600.6028_x-ww_61e65202
54: File (RW-)
C:\WINDOWS.0\WinSxS\x86_Microsoft.VC80.CRT_1fc8b3b9a1e18e3b_8.0.50727.6195_x-ww_44262b86
70: Section
\BaseNamedObjects\_ISWINTERNAL_EPT32_SHEX_K32_0_1c9aa25ea688500_7c80_S-1-5-21-1801674531-1078145449-1957994488-1004
78: File (RWD) C:\DOCUME~1\adam\LOCALS~1\Temp\IswTmp\Logs\ISWSHEX.swl
AC: Section
\BaseNamedObjects\_ISWINTERNAL_EPT32_SHEX_A32_0_1c98aa70f70ec00_77dd_S-1-5-21-1801674531-1078145449-1957994488-1004
100: Section
\BaseNamedObjects\CiceroSharedMemDefaultS-1-5-21-1801674531-1078145449-1957994488-1004
108: File (RW-) D:\downloads\Tera Term Pro\ttpro313\httplog.log
120: Section
\BaseNamedObjects\CTF.TimListCache.FMPDefaultS-1-5-21-1801674531-1078145449-1957994488-1004SFM.DefaultS-1-5-21-1801674531-1078145449-1957994488-1004
128: Section \BaseNamedObjects\ShimSharedMemory
138: Section \BaseNamedObjects\MSCTF.Shared.SFM.IAB
------------------------------------------------------------------------------
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PySerial could not open port COM4: [Error 5] Access is denied - please help "Adam" <adam@no_thanks.com> - 2012-06-26 21:12 -0700
Re: PySerial could not open port COM4: [Error 5] Access is denied - please help John Nagle <nagle@animats.com> - 2012-06-26 22:33 -0700
Re: PySerial could not open port COM4: [Error 5] Access is denied - please help "Adam" <adam@no_thanks.com> - 2012-06-27 02:10 -0700
Re: PySerial could not open port COM4: [Error 5] Access is denied - please help Paul <nospam@needed.com> - 2012-06-27 08:28 -0400
Re: PySerial could not open port COM4: [Error 5] Access is denied - please help "Adam" <adam@no_thanks.com> - 2012-06-27 08:26 -0700
Re: PySerial could not open port COM4: [Error 5] Access is denied - please help Paul <nospam@needed.com> - 2012-06-27 12:04 -0400
Re: PySerial could not open port COM4: [Error 5] Access is denied - please help "Adam" <adam@no_thanks.com> - 2012-06-27 10:41 -0700
Re: PySerial could not open port COM4: [Error 5] Access is denied - please help Paul <nospam@needed.com> - 2012-06-27 14:04 -0400
Re: PySerial could not open port COM4: [Error 5] Access is denied - please help "Adam" <adam@no_thanks.com> - 2012-06-27 13:40 -0700
Re: PySerial could not open port COM4: [Error 5] Access is denied - please help Grant Edwards <invalid@invalid.invalid> - 2012-06-27 21:18 +0000
Re: PySerial could not open port COM4: [Error 5] Access is denied - please help "Adam" <adam@no_thanks.com> - 2012-06-27 14:48 -0700
Re: PySerial could not open port COM4: [Error 5] Access is denied - please help Grant Edwards <invalid@invalid.invalid> - 2012-06-27 22:06 +0000
Re: PySerial could not open port COM4: [Error 5] Access is denied - please help Grant Edwards <invalid@invalid.invalid> - 2012-06-27 22:18 +0000
Re: PySerial could not open port COM4: [Error 5] Access is denied - please help Temia Eszteri <lamialily@cleverpun.com> - 2012-06-27 15:31 -0700
Re: PySerial could not open port COM4: [Error 5] Access is denied - please help "Adam" <adam@no_thanks.com> - 2012-06-27 15:51 -0700
Re: PySerial could not open port COM4: [Error 5] Access is denied - please help Grant Edwards <invalid@invalid.invalid> - 2012-06-27 23:24 +0000
Re: PySerial could not open port COM4: [Error 5] Access is denied - please help "Adam" <adam@no_thanks.com> - 2012-06-27 17:14 -0700
Re: PySerial could not open port COM4: [Error 5] Access is denied - please help Grant Edwards <invalid@invalid.invalid> - 2012-06-28 14:15 +0000
Re: PySerial could not open port COM4: [Error 5] Access is denied - please help "Adam" <adam@no_thanks.com> - 2012-06-28 13:31 -0700
Re: PySerial could not open port COM4: [Error 5] Access is denied - please help Roel Schroeven <roel@roelschroeven.net> - 2012-06-28 21:08 +0200
Re: PySerial could not open port COM4: [Error 5] Access is denied- please help "Adam" <adam@no_thanks.com> - 2012-06-28 14:48 -0700
Re: PySerial could not open port COM4: [Error 5] Access is denied - please help "David H. Lipman" <DLipman~nospam~@Verizon.Net> - 2012-06-27 08:28 -0400
Re: PySerial could not open port COM4: [Error 5] Access is denied - please help Grant Edwards <invalid@invalid.invalid> - 2012-06-27 14:53 +0000
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