[ALUG] Picasa 2 for Linux

[Mark Rogers]

Wayne Stallwood wrote:
> Wine isn't an emulator or a virtual machine, it is a reimplementation of
> the windows API that wraps the Windows executable and translates all the
> system calls to linux ones, because the core architecture is the same
> this is possible and a full platform emulation isn't required.
>   

This wording implies to me (probably not intentionally) that Wine is 
still an extra layer compared with Windows and brings performance 
drawbacks compared with a native environment.

Windows is, from the point of view of an application developer, a set of 
libraries of standard functions for stuff like drawing windows and 
managing user input (and network communications, sound, etc). A pretty 
big library, of-course, but it means that applications that use the 
Windows API tend to have a standard look and feel, and (in theory 
anyway) when you go from (say) Windows 3.x to Windows 9.x to XP to Vista 
the applications keep working (the APIs are still there) but the 
applications look new, because they use the new window decorations.

In other words, Windows is (as any operating system is) a layer between 
the hardware and the application. Wine, by implementing the Windows API 
on Linux and other platforms, means that applications that look for the 
"draw a window" function that Windows provides will find one that works 
the same and the application need never know anything is different.

In many cases that is case of mapping Windows functions to the 
equivalent Linux ones, as surprisingly enough there are functions to 
draw windows in X as well, they just have different names and parameter 
lists so a little magic between the two is needed. However there are 
also other functions that are implemented within Wine (rather than just 
mapped elsewhere). Whether a Windows application is faster in Windows or 
Linux therefore depends on which calls it makes, and whether the 
functions used are written "better" in Wine than in Windows (not 
uncommon), or if the underlying Linux function being mapped to is 
written better than its Windows counterpart.

In practise most Windows applications that run under Wine do run slower, 
albeit often not noticeably, under Wine, but that is a function more of 
the development that takes place on Wine being focused more on 
implementing the missing functions than on improving the ones that work, 
albeit slower. It is quite possible with the way Wine is implemented for 
it to be faster in some or most (all?) cases than Windows for the same 
application, but it's not there yet. It is quite feasible, for example, 
that in time the DirectX equivalents in Wine will allow Windows games to 
be faster on Linux than under Windows.

I only bother making this point because there is a general 
"understanding" that Wine is necessarily weaker than Wine, and that does 
not need to be the case. Not least because should games developers (for 
example) choose to target it then they have access to the underlying 
source code to improve on areas that are not working well for their 
application, something they cannot do with Windows. A Wine-based 
"Windows" game could be shipped with a complete optimised operating 
system and I'm sure that the result would be better than trying to run 
on a typical Windows desktop with all its little applications running in 
the background (not to mention viruses and spyware slowing the system 
down). Google ships a suitable version of Wine with Picassa to simplify 
the installation but I'm sure eny improvements they made to Wine along 
the way have been fed back for the general use by the rest of us in 
other Wine-based applications.

-- 
Mark Rogers // More Solutions Ltd (Peterborough Office) // 0845 45 89 555
Registered in England (0456 0902) at 13 Clarke Rd, Milton Keynes, MK1 1LG