I'm studying Principles of Communication Engineering by Wozencraft and Jacobs and the second chapter goes over probability theory, except it uses measure theoretic probability theory.
Here are my notes when reading about σ-algebras (sigma-algebra).
Wednesday, July 18, 2012
Thursday, July 5, 2012
Tuesday, July 3, 2012
Notes on pluggable optical I/O modules
Why have pluggable I/O interfaces
- Users can pick transceiver & cable for specific application
- Copper vs optical
- Active vs passive cable
SFP
- SFP (small form-factor pluggable)
- Conforms to the SFP multi-source agreement
- Up to 4 Gb/s
SFP+
- Enhancement of SFP
- Up to 10 Gbit/s
XFP
- XFP (10 gigabit small form factor pluggable)
- Conforms to the XFP multi-source agreement (also see INF-8077)
- Up to 10 Gb/s
- Electrical interface is XFI
XFP vs SFP+
- 10GbE can use both XFP & SFP+
- TBD
Overview of different standards
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| 40 GbE architecture |
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| 40 GbE implementation examples |
QSFP
- QSFP (quad small form-factor pluggable)
- For 40 Gb/s Ethernet etc.
- 4 channels in one interface
- Each channel up to 10 Gb/s, total 40 Gb/s
- NO CDR for re-timing
- Electrical interface XLPPI?
CFP
- CFP (C form factor pluggable) [C = latin centum = 100]
- Conforms to the CFP multi-source agreement
- For 40 Gb/s and 100 Gb/s Ethernet
- For long-haul Ethernet?
- Electrical interface XLAUI?
- CDR for re-timing
CXP
- CXP
- Active optical cable
- TBD
Monday, July 2, 2012
Can I use this embedded processor?
At work I'm asked if we can use a particular processor for a new system. Other than mechanical, electrical, and I/O considerations, software and tool support is very important.
When selecting processors for medium-sized embedded systems, I ask:
Is it a well-known architecture? For our applications, we stick with ARM, MIPS. We evaluated Intel, but they didn't meet our I/O requirements.
Linux support? I check Wikipedia and the Linux repository.
GCC support? I check the GCC repository.
ICE/JTAG support? I check Mentor Graphics and Macraigor.
When selecting processors for medium-sized embedded systems, I ask:
Is it a well-known architecture? For our applications, we stick with ARM, MIPS. We evaluated Intel, but they didn't meet our I/O requirements.
Linux support? I check Wikipedia and the Linux repository.
GCC support? I check the GCC repository.
ICE/JTAG support? I check Mentor Graphics and Macraigor.
Thursday, March 29, 2012
RFC 6090: Fundamental Elliptic Curve Cryptography Algorithms
RFC 6090: Fundamental Elliptic Curve Cryptography Algorithms
This note describes the fundamental algorithms of Elliptic Curve Cryptography (ECC) as they were defined in some seminal references from 1994 and earlier. These descriptions may be useful for implementing the fundamental algorithms without using any of the specialized methods that were developed in following years. Only elliptic curves defined over fields of characteristic greater than three are in scope; these curves are those used in Suite B.
Why I don't like using Java
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| Slimy Java installer bundling ad-ware |
My reasons for not liking Java (on the desktop, especially applets):
- Can't install it without Administrator privileges
- The installer is huge
- Java applets feel sluggish, and most of them don't look nice
- Java applets breaks my normal web viewing experience: odd widgets, captures mouse, can't go back etc.
- Need to update it every few months because of security concerns
- They bundle ad-ware, or what I assume is ad-ware because it's checked by default (to trick me into installing), and isn't something I would every install myself
Tuesday, March 27, 2012
Shell programming: pipefail
Today I discovered Bash's pipefail option. For a relevant blog post, see this.
So now all of my Bash scripts will begin with "set -e; set -o pipefail;"
So now all of my Bash scripts will begin with "set -e; set -o pipefail;"