With his text, VHDL: Modular Design and Synthesis of Cores and Systems, professor Z. Navabi of Northeastern University dives into VHDL as a modern software modeling tool for ASIC and FPLD designs. He provides a quick overview of implementing VHDL designs, testbenches, and configurations; and then continues to build upon this foundation with an in-depth treatment of the VHDL language. The book concludes with designing testable cores and the full development of a processor core.

Following his text and implementing each of the chapter problems, I have noticed a few areas of his language treatment that were ignored both in my classroom studies as well as my industry experience. One such language feature is the VHDL block with guarded signal assignment.

The VHDL block is essentially the concurrent analogy to the sequential process. Both may be used to create latches and flip-flops. As an example, the following shows a D flip-flop in both concurrent (block) and sequential (process) forms.

-- Concurrent D flip-flop with rising edge sensitivity.
dff_concur: BLOCK (clk = '1' AND NOT clk'STABLE)
BEGIN
  q <= GUARDED d;
END BLOCK dff_concur;

-- Sequential D flip-flop with rising edge sensitivity.
dff_sequent: PROCESS (clk)
BEGIN
  IF (clk = '1' and clk'EVENT) THEN
    q <= d;
  END IF;
END PROCESS dff_sequent;

I cannot help but wonder if synthesis tools treat the concurrent block form any differently.

For the new year transition of 2008 to 2009 a large number of once Mobil gasoline stations have been re-branded overnight. Now featuring the Sunoco brand, these stations provided no announcement of change of ownership. I assume that the change in logo was only a change in upper management; the appearance of so many blue stations changing to yellow confused my driving landmarks. The stations I noticed changing brand were in the Finger Lakes area of New York State. Some people in Virginia State have been discussing this same phenomenon for several years.

On November 14th I was in a serious car accident that landed me in the Strong Memorial hospital here in Rochester. A month later, I am still in progress of recovering. Minimal physical injury was sustained; but the accident has left me to re-evaluate a lot of what I believe and how I have chosen to live up to this point.

Sorting one's life out when it is filled with question marks is a difficult season; but I am choosing to look forward with this as a time to redevelop courage and faith in anticipation of many years yet to come.

The following are a few interesting Christian apologetics sites—with video clips—that I have been looking at this week.

Global Vision Channel

The Truth Project

A tip for Linux users: if you use MPlayer to view the footage, you will probably need the following configuration option:

   rtsp-stream-over-tcp=yes

Otherwise, VLC is probably the only F/OSS player currently capable of viewing the streams without any sort of issue. The Firefox addon MediaPlayerConnectivity is also useful.

In an attempt to expedite my thesis work, last month I purchased a new laptop: Dell Inspiron 640m. A high-end MacBook would have been preferable; but unfortunately, the Mac would have been near double the price for the same raw computational power. (Already I miss the keyboard and DVI video output.)

The performance for this model—both in terms of computation and battery life—is quite impressive and makes all of my other machines appear to be obsolete by comparison. Needing a competent workstation for hardware and software design, I removed the preloaded Windows Vista Business and installed Gentoo Linux; and as such, I have written a page of notes with details.