[GRASS-user] shared access to mapsets

[Duncan Golicher]

After going through all the steps I was still locked out! I got the 
message that I am currently running GRASS in selected mapset, concurrent 
use not allowed. I then had some trouble resetting everything to get 
back in on the old machine. There must be a simpler solution! (?) Note 
that the idea of making new locations is fine, but I have the data on an 
external hard drive that I just want to move between two PCs. Any 
further suggestions would be very welcome.


Glynn Clements wrote:

>[CC'd to grass-dev]
>
>Duncan Golicher wrote:
>
>  
>
>>Can anyone answer a very simple question. I am running grass6.1 under 
>>Cygwin with all my data on an external hard drive. I recently installed 
>>grass on a new PC. I now can't enter any of the mapsets I created on the 
>>first machine from the second and can only get read access to them from 
>>new mapsets. I have a different username on the second PC so I obviously 
>>don't have permissions. What I can't find out, after Googling and 
>>searching the list, are the steps I should take to change the 
>>permissions, or perhaps the username in cygwin, so I can just share the 
>>database between the two machines. 
>>    
>>
>
>Apart from any access controls implemented by the OS, GRASS itself
>won't let you select a mapset as the current mapset unless you are the
>owner of the mapset directory.
>
>[This check is disabled on the native Windows version, as the
>functions which it uses aren't present there.]
>
>Note to developers: I'm starting to think that we should seriously
>reconsider this restriction. Now that the .gislock file is in the
>mapset directory rather than the home directory, is there any point in
>having this check?
>
>In general, to change the owner of a file under Windows XP Pro (I
>don't know if XP Home is any different), perform the following
>(excessively complex) sequence of steps:
>
>[The process is complicated by the fact that even an administrator
>cannot "give away" files; you have to permit the intended recipient to
>take ownership, then have the recipient actually take ownership of the
>files.]
>
>+ Log in using either the account which owns the file or an account
>with administrator privileges.
>
>+ In Explorer, choose the "Folder Options ..." item from the "Tools"
>menu.
>
>+ Select the "View" tab in the Folder Options dialog.
>
>+ Uncheck the "Use simple file sharing (Recommended)" option.
>
>+ Click "OK".
>
>+ In Explorer, select the file or directory whose ownership you wish
>to change.
>
>+ Select the "Properties" option from either the "File" menu or the
>context menu (or Alt+Enter).
>
>+ Select the "Security" tab (this tab is only available once you have
>disabled simple file sharing as directed above).
>
>+ Click the "Advanced" button.
>
>+ The "Permissions" tab should be selected.
>
>+ Click the "Add..." button.
>
>+ Enter the name of the user to whom you wish to transfer ownership.
>
>+ Press OK.
>
>+ Check the box in the "Take Ownership" row and the "Allow" column.
>
>+ Press OK.
>
>+ Check the "Replace permission entries ..." option.
>
>+ Press OK.
>
>+ Press OK (for the Properties dialog).
>
>+ Log in as the user to whom you wish to transfer ownership.
>
>+ Disable simple file sharing as directed above (this is a per-user
>setting).
>
>+ Select the mapset directory in Explorer.
>
>+ Select the "Properties" option from either the "File" menu or the
>context menu.
>
>+ Select the "Security" tab.
>
>+ Click the "Advanced" button.
>
>+ Select the "Owner" tab.
>
>+ Select your name from the list.
>
>+ Check the "Replace owner on subcontainers and objects" option.
>
>+ Press OK.
>
>+ Press OK (for the Properties dialog).
>
>Optional: once you've changed the owner, you can remove the "take
>ownership" permission entry. Also, you can re-enable simple file
>sharing if desired; this will hide the Security tab in the Properties
>dialog.
>
>Tip: to save having to switch between your normal account and an
>administrative account, create a shortcut to "C:\WINDOWS\explorer.exe"
>with the "Run with different credentials" option enabled (click the
>"Advanced" button in the shortcut's properties dialog). This lets you
>do file management using an administrative account without having to
>switch between logins. A few things don't quite work, e.g. 
>notifications (you have to manually refresh the view with F5 whenever
>you change something).
>
>  
>


-- 
Dr Duncan Golicher
Ecologia y Sistematica Terrestre
Conservación de la Biodiversidad
El Colegio de la Frontera Sur
San Cristobal de Las Casas, 
Chiapas, Mexico

Email: dgoliche at sclc.ecosur.mx 

Tel: 967 674 9000 ext 1310
Fax: 967 678 2322

United Kingdom Skypein; 020 7870 6251
Skype name: duncangolicher