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Embedded Ethernet and Internet Complete
from the tininess dept.
| Embedded Ethernet and Internet Complete | |
| author | Jan Axelson |
| pages | 482 |
| publisher | Lakeview Research LLC |
| rating | 9 |
| reviewer | Tim Drury |
| ISBN | 1931448000 |
| summary | Designing with Ethernet in embedded systems. |
Axelson's writing style is a little difficult to describe. At times you feel you could be reading a "For Dummies" (TM, Patent Pending, Please Don't Sue Me) book since her writing style is so easy to digest, but simultaneously, she's covering quite a bit of depth and breadth which you expect from a more advanced volume. This seems paradoxical yet the point stands: you will retain what you read from Axelson.
Contents
The networking basics sections describes the network protocol stack (Ethernet, TCP, UDP, and IP frames), collision mediation, and how to use a sniffer (Ethereal in her case). It's of moderate detail suitable for an introduction. Much more detail is provided in later sections. Axelson also uses this section to describe, in good detail, the Ethernet media access control scheme that arbitrates which device talks when and how to handle packet collisions.
These network hardware sections are an in-depth description of cabling (Cat-5, fiber, wireless, etc.) which includes bit rate, max lengths, encoding types, etc. She also includes a small section on building your own Cat-5 for you really cheap Joes. There is a cursory review of hubs, switches, and routers and the network architecture limitations imposed by each for each type of network cabling.
Axelson goes on to describe some common embedded systems including TINI (Java-based) and Rabbit (C-based), which are the two systems she uses and provides examples for. Thankfully, keeping with her Circuit Cellar hobbyist tradition, both of these systems are very affordable to the casual hobbyist. She also provides detailed descriptions of some common Ethernet chipsets down to the registers (at least for the ubiquitous NE2000 registers). Also included are schematics for typical interfaces to these chipsets for the reader who wishes to build his own Ethernet-aware embedded system.
The Internet basics sections describe the various connection solutions such as dial-up, DSL, and satellite and the benefits and limitations of each. Axelson provides a cursory discussion of firewalls, domain naming and DNS, URL dissection, DHCP, NAT, ARP, and ICMP. These sections, I believe, are suitably informational for the embedded system designer, but not exhaustive. She then launches into an in-depth discussion of IP addressing and the IPv4 header which, in my opinion, is required for anyone working at the packet level. Axelson uses some data from Ethereal to support her discussion of IPv4. She also reminds us that Ethernet communications need not use the full TCP or UDP stack but can, if desired, use only IP-wrapped packets or even just Ethernet frames to communicate.
We finally get to some real code in the TCP/UDP socket communication sections. Axelson begins with samples of UDP, then TCP, socket communications. She bounces back and forth between Rabbit C code and TINI Java code. Both sets of examples are properly threaded so as to be more than just academic-example hogwash. Then she delves into the details of UDP and TCP, beginning with descriptions of the frame headers, then concludes with handshaking/flow-control (SYN-ACK and so forth). She includes suggestions for other books that continue even deeper into socket communications which is very nice especially since they aren't gratuitous promotions from the same publisher. (They are, in fact, from two different publishers.) By the way, Lakeview Research is her own company, so Axelson self-publishes. Nice.
Fully half of the book is dedicated to describing the top layer of the protocol stack: applications. Specifically, HTTP client and server, receiving and sending email, and FTP client and server. The HTTP samples leverage the bundled TINI and Rabbit libraries to serve web pages. Axelson also includes examples of running a third-party servlet engine (Tynamo) on the TINI system. Similarly, the sections for sending and receiving email and the FTP client/server leverage the bundled libraries of Rabbit and TINI. I find this appropriate -- why write low-level socket code when there are available libraries that perform all the grunge work for you? If you do need to modify the support libraries, the Rabbit Dynamic C source code is available, but the TINI Java library source code is not.
The last few sections of the book discuss security. Axelson doesn't leave security as a footnote, as she does include sample code for basic authentication, but she also doesn't give security the depth she provided the other topics. Sure, security is a huge topic which would take numerous volumes to cover, but I thought this section could use a little more detail. I would like to have seen example code in the sections on encryption (both symmetric and asymmetric). I would like to have seen what is required to enable SSL in the web server examples. If these were not to be provided, I would have like to have her cite other books which would have completed her discussion as she did in the raw socket communications sections.
What Could Be Improved
I don't really like the large font and spacing used in this book; I prefer a more condensed text which probably would have reduced the book size some 20% or so. But as I think about it, perhaps this is one characteristic that make Axelson's books so easy to read: there is little eye-strain.
In the hardware sections, I would like to have seen even a trivial example of an NE2000 device driver. It wouldn't even have to be an Ethernet-compliant driver, just something that demonstrates sending and receiving with flow and error control. This would be useful if you were building your own device which didn't include a protocol stack.
In the low-level socket communications sections, I would have preferred to see two things. First, I would have liked to see a test program that communicated between the C-based Rabbit and the Java-based TINI to demonstrate a heterogeneous distributed embedded system. Second, I would have like to seen an echo test program. When prototyping communications to any embedded system I always write an echo test program which begins by transmitting a small message with a numeric value, then listens for messages, increments their value, and sends them back out. Validation testing is performed during this process. This program is easy to write and a great diagnostic tool.
Conclusion
Since this is my first book review I can't objectively give it an absolute rating like 4 stars or 8/10 since you have nothing to compare my judgment to. However, I can say that this book is well worth the money spent which, all too often, isn't the case anymore these days. I think Axelson has struck an ideal blend of detail where needed and summary when detail is not required. The book is organized well and should satisfy both the casual bathroom reader and the rigorous, horribly-cracked-binding, lab-bench-reference reader.
I like Axelson's writing style; it's an ideal blend of assume I'm an idiot-style when you need it and in-depth when you want to dig. Another great point: she doesn't stuff the appendices with data sheets, API documentation, or command syntax references. All those can be found on-line and have no place in a book, where they quickly become dated. If you absolutely must have a definite rating, then I'd give it an 8 or 9 out of 10. I would place books like Stevens' Unix Network Programming at a solid 10 and about 99% of the other books out there around a 5.
You can purchase Embedded Ethernet and Internet Complete from bn.com. Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page.
hehe (Score:4, Funny)
(http://www.peterswift.org/)
Thanks for the review (Score:5, Interesting)
(Last Journal: Monday October 23 2006, @12:44PM)
However, if the device or embedded system you're working on is already designed and your goal is to network-enable it, what do you guys turn to? From what I've seen around, Lantronix XPort [lantronix.com] is a good option for cheap embedded device servers, but what else is available?
urrrgh (Score:1, Insightful)
Uhh.. Ethernet uses frames, IP uses packets.
Mr first review of a review (Score:2, Funny)
(http://www.snapfood.com/)
Code samples for the book.... (Score:5, Informative)
(http://tomcopeland.blogs.com/)
And the usual code quality report courtesy PMD [sf.net]:
Complete Internet (Score:1, Funny)
(http://slashdot.org/)
I wonder if the book includes a CD?
How about a USB starter kit? (Score:2)
Re:How about a USB starter kit? (Score:4, Informative)
I can recommend the Rabbit processor (Score:3, Informative)
w
Bigger Is Sometimes Better (Score:1, Interesting)
By the way, Lakeview Research is her own company, so Axelson self-publishes. Nice.
While I admire Jan for making a viable business out of something she obviously loves, she seems to have bitten off a lot for herself. After building some prototype hardware based on Parallel Port Complete, I found the book had an error making my hardware quite crippled (a software workaround was possible, but inefficient and ugly). I pointed it out to her via e-mail, but it was never resolved to my satisfaction. AFAIK, to this day that error still exists.
I began to wonder what it must be like to self-publish and then deal with an error report when you are author, editor, publisher and tech support all rolled into one. A bigger company may not have handled my issue any better, but certainly it would have the resources do so easier than a small self-publisher. My two cents are: Jan's stuff is great for hobbyists, but beware of accuracy.
other good embedded IP resources (Score:3, Informative)
Cirrus Logic CS8900a Ethernet module [cirrus.com], it works in 8-bit mode
Buy a CS8900 [embeddedethernet.com] module.
** Shameless plug **
Read my thesis [lehigh.edu] about how to put it all together.
Another book (Score:3, Interesting)
It may be a better fit for those of us with absolutely no background, really short attention spans and very strange ideas about what might be cool to do to a toilet...
TINI Java Library Source Code (Score:1, Informative)
The author is not a woman (Score:2)
Cat-5? (Score:2)
(http://iantri.ath.cx/)
Assuming they mean making up network cable and not actually fabricating CAT-5 wire, why on Earth would you NOT make your own cables?
CDN$.30/foot + connectors is a hell of a lot cheaper than the precut lengths that are only available in standard sizes (25ft, 50ft), and it's very easy..
Other work by Jan Axelson (Score:2, Informative)
Dan Danknick
Technical Editor (of both)
Re:Can you do it or can't you? (Score:1, Funny)
Re:A woman wrote this? (Score:2)
(http://jo-ham.com/)
The smartest person I know is female.
Free clue for Sam Duncan... (Score:2, Insightful)
Re:A woman wrote this? (Score:1)
(http://slashdot.org/)