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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN">
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<title>An Alternative to Top Issue 19</title>
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<H4>
"Linux Gazette...<I>making Linux just a little more fun!</I>"
</H4>
<P> <HR> <P>
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<center><h1>QPS, A New Qt-Based Monitor</h1></center>
<center>
<h4><a href="mailto: layers@vax2.rainis.net">by Larry Ayers</a></h4>
</center>
<P>
<hr>
<center><h3>Introduction</h3></center>
<p>The Qt C++ software development toolkit, by Norway's Troll Tech, has been
available long enough now that applications are beginning to appear which use
Qt rather than Motif, Xlib or Tcl/TK. Programs developed with Qt have an
identifiable and distinctive appearance, with some resemblance to both Windows
and Motif. There has been some resistance in the Linux community to
widespread adoption of the toolkit due to its hybrid licensing arrangement.
The toolkit is freely available in the Linux version, and its use in the
development of free, GNU-ish software is free and unrestricted, but for other
platforms and for commercial Linux software Qt is a commercial product.
<p>Remember when Tcl/Tk began to become widely used a couple of years ago?
Applications and utilities written with the toolkit began to proliferate, one
reason being that the learning curve is relatively gentle and a quick X
interface to a command-line utility could be contrived in a short time. C
programmers found that the guts of a program could be written in C, while the
tricky X-windows interface could be quickly put together with Tcl/Tk. This
benefited the Linux community as a whole, making it easier for new users and
developers to gain a foothold on the sometimes forbiddingly steep unix
terrain.
<p>Qt is an entirely different sort of toolkit than Tk, since it is based on
C++ and doesn't have the interpreted script layer of Tk. (It more closely
resembles Bruce Wampler's <a href="http://www.cs.umn.edu/~wampler">V</a>
package, described in the Dec. 1996 issue of Linux Journal.) In order to run QT
applications the <em>libqt</em> shared lib must be available as well as a
small executable, <em>moc</em>. The Qt header (include) files are needed as
well to compile these applications from scratch. The Qt source package is
available from <a href="ftp://ftp.troll.no/qt">the Troll Tech FTP site</a>.
Many small sample applications and demos, as well tutorials and ample
documentation, are included in the package.
<center><h3>QPS</h3></center>
<p><a href="mailto: f91-men@nada.kth.se">Mattias Engdegrd</a> has recently
written and released a process monitor similar to <em>top</em>, the classic
interface to <em>ps</em>. <em>Top</em>, though a character-mode application,
is commonly run in an xterm or rxvt window in an X session. There is one
problem with <em>top</em> in a window; scrolling down to the bottom of the
process list doesn't work, so the entries at the bottom are inaccessible
without resizing the window. There may be a way to do this, but I haven't
been able to find one. A minor issue, I suppose, since the
ordering of the entries can be easily toggled so that either the most
memory-intensive or the most CPU-intensive processes appear at the top.
<p>Qps is a more X-friendly application than <em>top</em>, with scrollbars and
a mouse-oriented interface. Clicking on any of the header categories, such as
%CPU, SIZE, or %MEM, will sort the processes in descending order.
<kbd>Alt-k</kbd> will kill a highlighted process. A series of bar-graphs
along with an xload-like meter form a status bar at the top of the window.
This can be toggled on and off from the menu-bar. When Qps is iconified the
icon is the small xload-like pane from the status-bar, which is a nice touch.
<p>Here's a screenshot:<br>
<p>
<img alt="Qps screenshot" src="./gx/ayers/qps.gif">
<hr>
<p>Qt applications don't use the X resources typical of most X programs; one
result of this is that Qps seems to be confined to the default white, gray,
and black color scheme. It <em>can</em> generate a resource file in your home
directory which specifies which fields you'd like to see and whether the
status-bar should be visible or not.
<p>Qps could be thought of as a sort of second-generation Linux utility,
written for users who rarely work from the console and boot directly into an X
session. It should fit in well with the <a href="http://www.kde.org">KDE</a>
suite of applications, which are also being developed with Qt. Though it uses
more memory than <em>top</em> in an rxvt window, I find myself using it often
while running X. I think this is a solid, dependable application and deserves
attention from the Linux community.
<center><h3>Availability</h3></center>
<p>Currently the Qps-1.1 source is in the Sunsite
<a href="ftp://sunsite.unc.edu/pub/Linux/Incoming">Incoming</a> directory, but
will most likely end up in the
<a href="ftp://sunsite.unc.edu/pub/Linux/system/status">status</a> directory.
An alternate Swedish site is
<a href="ftp://ptah.lnf.kth.se/pub/qps">here</a>.
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<P> <hr> <P>
<center><H5>Copyright © 1997, Larry Ayers<BR>
Published in Issue 19 of the Linux Gazette, July 1997</H5></center>
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