Hernán Grecco: PyVISA command-line utilities

PyVISA is a Python frontend for the VISA library that enables controlling all kinds of measurement equipment through GPIB, RS232, USB and Ethernet among others interfaces.

If you are following the development of PyVISA you might have seen that we have recently made the visa module executable to provide a few useful utilities. To try this, you need to update to the latest PyVISA:

$ pip install -U https://github.com/hgrecco/pyvisa/zipball/master

First, we now provide a simpler way to get debug information:

$ python -m visa info
Machine Details:
   Platform ID:    Darwin-10.8.0-x86_64-i386-32bit
   Processor:      i386

Python:
   Implementation: CPython
   Executable:     /Users/grecco/envs/lantz/bin/python
   Version:        3.2.3
   Compiler:       GCC 4.2.1 (Apple Inc. build 5666) (dot 3)
   Bits:           32bit
   Build:          Apr 10 2012 11:25:50 (#v3.2.3:3d0686d90f55)
   Unicode:        UCS2

PyVISA Version: 1.6.1

Backends:
   ni:
      Version: 1.6.1 (bundled with PyVISA)
      #1: /Library/Frameworks/visa.framework/visa:
         found by: auto
         bitness: 32
         Vendor: National Instruments
         Impl. Version: 5243392
         Spec. Version: 5243136
   py:
      Version: 0.1.dev0
      ASRL INSTR: Available via PySerial (10.8.0)
      TCPIP INSTR: Available
      USB INSTR: Available via PyUSB (1.0.0rc1). Backend: libusb0


Notice also that more useful information is given, including details about the different backends (in this case ni and py).

Another utility is the VISA shell which was taken from the Lantz project. It provides a way to list, open and query devices. It also allows you to get (and in the near future set) attributes. The shell has in-built help, autocomplete and

$ python -m visa shell
Welcome to the VISA shell. Type help or ? to list commands.

(visa) list
( 0) ASRL2::INSTR
( 1) ASRL1::INSTR
(visa) open ASRL1::INSTR
ASRL1::INSTR has been opened.
You can talk to the device using "write", "read" or "query".
The default end of message is added to each message
(open) attr
+-----------------------------+------------+----------------------------+-------------------------------------+
|          VISA name          |  Constant  |        Python name         |                 val                 |
+-----------------------------+------------+----------------------------+-------------------------------------+
| VI_ATTR_ASRL_ALLOW_TRANSMIT | 1073676734 |       allow_transmit       |                  1                  |
|    VI_ATTR_ASRL_AVAIL_NUM   | 1073676460 |      bytes_in_buffer       |                  0                  |
|      VI_ATTR_ASRL_BAUD      | 1073676321 |         baud_rate          |                 9600                |
|    VI_ATTR_ASRL_BREAK_LEN   | 1073676733 |        break_length        |                 250                 |
|   VI_ATTR_ASRL_BREAK_STATE  | 1073676732 |        break_state         |                  0                  |
|    VI_ATTR_ASRL_CONNECTED   | 1073676731 |                            |          VI_ERROR_NSUP_ATTR         |
|    VI_ATTR_ASRL_CTS_STATE   | 1073676462 |                            |                  0                  |
|    VI_ATTR_ASRL_DATA_BITS   | 1073676322 |         data_bits          |                  8                  |
|    VI_ATTR_ASRL_DCD_STATE   | 1073676463 |                            |                  0                  |
|  VI_ATTR_ASRL_DISCARD_NULL  | 1073676464 |        discard_null        |                  0                  |
|    VI_ATTR_ASRL_DSR_STATE   | 1073676465 |                            |                  0                  |
|    VI_ATTR_ASRL_DTR_STATE   | 1073676466 |                            |                  1                  |
|     VI_ATTR_ASRL_END_IN     | 1073676467 |         end_input          |                  2                  |
|     VI_ATTR_ASRL_END_OUT    | 1073676468 |                            |                  0                  |
|   VI_ATTR_ASRL_FLOW_CNTRL   | 1073676325 |                            |                  0                  |
|     VI_ATTR_ASRL_PARITY     | 1073676323 |           parity           |                  0                  |
|  VI_ATTR_ASRL_REPLACE_CHAR  | 1073676478 |        replace_char        |                  0                  |
|    VI_ATTR_ASRL_RI_STATE    | 1073676479 |                            |                  0                  |
|    VI_ATTR_ASRL_RTS_STATE   | 1073676480 |                            |                  1                  |
|    VI_ATTR_ASRL_STOP_BITS   | 1073676324 |         stop_bits          |                  10                 |
|    VI_ATTR_ASRL_WIRE_MODE   | 1073676735 |                            |                 128                 |
|    VI_ATTR_ASRL_XOFF_CHAR   | 1073676482 |         xoff_char          |                  19                 |
|    VI_ATTR_ASRL_XON_CHAR    | 1073676481 |          xon_char          |                  17                 |
|     VI_ATTR_DMA_ALLOW_EN    | 1073676318 |         allow_dma          |                  0                  |
|    VI_ATTR_FILE_APPEND_EN   | 1073676690 |                            |                  0                  |
|    VI_ATTR_INTF_INST_NAME   | 3221160169 |                            | ASRL1  (/dev/cu.Bluetooth-PDA-Sync) |
|       VI_ATTR_INTF_NUM      | 1073676662 |      interface_number      |                  1                  |
|      VI_ATTR_INTF_TYPE      | 1073676657 |                            |                  4                  |
|       VI_ATTR_IO_PROT       | 1073676316 |        io_protocol         |                  1                  |
|   VI_ATTR_MAX_QUEUE_LENGTH  | 1073676293 |                            |                  50                 |
|   VI_ATTR_RD_BUF_OPER_MODE  | 1073676330 |                            |                  3                  |
|     VI_ATTR_RD_BUF_SIZE     | 1073676331 |                            |                 4096                |
|      VI_ATTR_RM_SESSION     | 1073676484 |                            |               3160976               |
|      VI_ATTR_RSRC_CLASS     | 3221159937 |       resource_class       |                INSTR                |
|  VI_ATTR_RSRC_IMPL_VERSION  | 1073676291 |   implementation_version   |               5243392               |
|   VI_ATTR_RSRC_LOCK_STATE   | 1073676292 |         lock_state         |                  0                  |
|     VI_ATTR_RSRC_MANF_ID    | 1073676661 |                            |                 4086                |
|    VI_ATTR_RSRC_MANF_NAME   | 3221160308 | resource_manufacturer_name |         National Instruments        |
|      VI_ATTR_RSRC_NAME      | 3221159938 |       resource_name        |             ASRL1::INSTR            |
|  VI_ATTR_RSRC_SPEC_VERSION  | 1073676656 |        spec_version        |               5243136               |
|     VI_ATTR_SEND_END_EN     | 1073676310 |          send_end          |                  1                  |
|   VI_ATTR_SUPPRESS_END_EN   | 1073676342 |                            |                  0                  |
|       VI_ATTR_TERMCHAR      | 1073676312 |                            |                  10                 |
|     VI_ATTR_TERMCHAR_EN     | 1073676344 |                            |                  0                  |
|      VI_ATTR_TMO_VALUE      | 1073676314 |                            |                 2000                |
|       VI_ATTR_TRIG_ID       | 1073676663 |                            |                  -1                 |
|   VI_ATTR_WR_BUF_OPER_MODE  | 1073676333 |                            |                  2                  |
|     VI_ATTR_WR_BUF_SIZE     | 1073676334 |                            |                 4096                |
+-----------------------------+------------+----------------------------+-------------------------------------+
(open) close
The resource has been closed.



Again, this release is only possible thanks to the contribution of a lot of people that contributed bug reports, testing and code. Thanks to everybody!

Submit your bug reports, comments and suggestions in the Issue Tracker. We will address them promptly.

Read the development docs: https://pyvisa.readthedocs.org/en/master/
or fork the code: https:/https://github.com/hgrecco/pyvisa/

Gustavo Campanelli: Como recuperé 20 GB de mi disco rígido

Recientemente vi que el juego DC Universe Online se podía jugar gratuitamente, así que decidí darle una oportunidad y bajarlo. Luego de 3 días de descarga (a bajas velocidades mientras jugaba otras cosas, a altas velocidades de noche) lo tuve disponible. Jugué unas 7 horas. y debo decir que me resultaron bastante entretenidas. El comienzo, el escape de la nave de Brainiac, está muy bien diseñado

Marcos Dione: testing-qt4-applicationswith-slots-and-signals

A few days ago someone said something[1] that reminded me about my audio player, which I had abandoned for more than a year already. The reason was mostly that the two Phonon backends, VLC and gstreamer, for some reason or other couldn't play the files I had without any gaps between songs.

To be honest, the first bug end up being me not properly encoding the filenames. If you first URL-encoded the filename and then built a Q/KURL with that, then it's all fine. It took me more than 12 months and a few rereads of the thread to realize it. Fixes apart, it seems that the bug still exists for other instances of gstreamer errors, so we're not out of the woods. In any case, I switched to the VLC backend and it seems that now is able to fire the aboutToFinnish() signal properly, so for the moment I'm using that.

All that is fine, but that's not what I wanted to talk about in this post. Given that this project largely precedes my interest on testing, it has no testing at all. Most of the project is straightforward enough to almost no need any, but there's a critic part that would not suffer at all if it had any, namely the Collections handling, including passing files from one to another and automatically updating new/removed Songs[2].

So after fixing the bug mentioned above I tried to figure out the current state of affaires regarding Collections, and boy, they're in bad shape. The code was locally modified, never commited, deactivating any notifications of filesystem changes (new or removed files), and other code I can't really understand the purpose of.

Because if this last detail is that I decided to start testing three classes: Collection, which handles a set a Songs with a common root directory; CollectionAggregator, which handles a set of collections and should coordinate moving a Song from one Collection to another; and CollectionIndexer, which scans from a Collection's root dir to find Songs.

All went fine while I tested the first class, Collection. There was a tricky part where I had to setup a QApplication in order to make signals work. The problems began when I started testing CollectionIndexer. Tests started blocking endlessly, signals stopped being either emited or firing the connected slots, life was bad.

I tried to search the available documentation and mailing lists for a hint about the problem, but besides a quite complex example that didn't seem to properly converge to anything useful, I was mostly on my own.

This morning I got my eureka moment: I noticed that if I executed each test class by itself, it worked, but both at the same time blocked and never finished. Then I remembered something said in QApplication's documentation:

For any GUI application using Qt, there is precisely one QApplication object, no matter whether the application has 0, 1, 2 or more windows at any given time.

That was it: I was creating the application, first in the setUp() method, then as a class attribute, but I had one test class per class to test, each in its own file. Somehow this last fact lead me to think that somehow they were executed in separate processes, which is not true. Luckily, even with this limitation, there's none on the amount of times you can exec_() and quit() the same instance, so that's what I did: I created only one instance and reused it everywhere. I was already doing that for each test method, but again, somehow having several files mislead me to think they were isolated from each other.

So now all my unit tests work without mysteriously blocking forever. Now I just hope I can keep riding the success wave and bring satyr into good shape. A new release wouldn't hurt.


[1] No matter how much I try, I can't get any vaguer.

[2] Ok, maybe the Player/Playlist combo wouldn't hurt to have UTs either.


satyr pykde python

Hernán Grecco: Communicating with instruments using PyVISA but without NI-VISA

PyVISA is a Python frontend for the VISA library that enables controlling all kinds of measurement equipment through GPIB, RS232, USB and Ethernet among others interfaces.

Starting form version 1.6, PyVISA allows to use different backends. The cool thing is that your code remains the same, except the line in which you instantiate the resource manager (which tells which backend to use).

A few days ago I blogged about one of such alternative backends called PyVISA-sim which allows your to mock the presence of instruments (in cased that you missed the announcement, is here). Today I am making public a second backend.
 
Until now, talking to instruments via PyVISA required that you had National Instruments VISA library installed in your system. This works most of the time, for most people. But NI-VISA is a proprietary library that only works on certain systems. That is when PyVISA-py jumps in. It is an implementation of message based communication (Serial/USB/Ethernet) using Python and some well developed, easy to deploy and cross platform libraries (PySerial/PyUSB/Python Standard Library). In the near future it will also use linux-gpib to provide access to GPIB instruments in linux.

Cool, right? PyVISA without NI-VISA.

It actually started with an issue in the PyVISA tracker. A user wanted to use the LibreVISA library: an open source alternative to NI-VISA. While in principle this could work, it does not as LibreVISA is still incomplete. That is when it became obvious ... why not implementing parts of the VISA library in Python + friends? It would be open source, should be much easier to hack and compatible with PyVISA.

PyVISA-py is still young. Some very basic functionality is there but there still things to be done in order to implement all VISA features for message based sessions. But you can give it a try and provide feedback and why not code:

Just install (or upgrade) PyVISA 1.6 which is currently only available from GitHub:

$ pip install -U pyvisa

And then install:

$ pip install -U https://github.com/hgrecco/pyvisa-py/zipball/master

and then just instantiate your ResourceManager

import visa
rm = visa.ResourceManager('@py')

Notice that the rest of your code will be EXACTLY the same.

Remember that this is an early preview. We need your help to get it to the ready. Submit your bug reports, comments and suggestions in the Issue Tracker. We will address them promptly.

Or fork the code: https://github.com/hgrecco/pyvisa-py/

Joaquin Sorianello: Pixels de colores.

Desde que tengo memoria, pintar cosas con colores me costó muchísimo.

En la escuela primaria, por ejemplo, mis cuadernos tenian dibujos en lápiz negro, y grisados. Mi abuelo dibujaba así y lograba efectos buenísimos.

Para mi los lápices de colores se transformaban en bestias indomables que desparramaban color sin llegar a gustarme.

Cuando empecé a programar, siempre me escudé en "Yo hago la lógica, que otro le ponga colores". En fin, años de traumas por no poder combinar dos colores o mas.

Hace un par de años, en una de las visitas a mi genial sobrina Catalina, mis tios le mandaron conmigo una caja de acuarelas, y yo le llevaba libros de Oliver Jeffers.

Fue asombroso.

Probablemente tendría que escribir un post entero sobre como  el hacer actividades en las que nos sentimos inseguros, junto con niños, puede cambiar nuestras perspectivas.

El resultado, montones de dibujos "en colaboración" con mi sobrina,  analizamos juntos los dibujos de Jeffers y tratamos de darnos cuenta como lograba los efectos.

En ese momento, me di cuenta que necesitaba volver a dibujar y mejorar mi tema con los colores.

Miré videos, lei tutoriales sobre teoria del color y nada parecia mejorar.

Entonces mi primo Nahuel, me recomendó una charla, que me hizo cambiar mucho mi forma de ver las cosas:


En resumen, si no van a ver el video completo:

Dibujar todos los días, analizar que nos gusta de las cosas que nos gustan, copiar y transformar.

Una de esas cosas que hice fue mi portada para twitter usando pixeles grandotes. Para eso usé inkscape, y fue bastante engorroso.



Terminada la portada, me animé a hacer un patron para usar de fondo, el resultado... triste...

Es difícil hacer patrones repetitivos, sin que "el atomo" que se repite sea demasiado obvio.

Por eso, luego de escribir toneladas de javascript para el proyecto en el que estoy laburando, decidí tomarme un rato de programación lúdica, y armé pixium, una herramienta muy sencilla, para crear patrones.

El resultado, adictivo.

Como conclusión: dibujar y programar son cosas parecidas, ambas implican creatividad, y la mejor manera de estimularla es haciendo y analizando. Eso, creo, es fundamental para aprender.

Marcos Dione: virtualbox-could-not-find-xorg-or-xfree86

At work we have Windows workstations, but we develop for Linux (don't ask; in my previous mission in another MegaCorp we had a similar setup for admining Linux servers...). We have access to devel machines via ssh and Samba, but the setup is laughable. I won't go too much into details because it's embarrassing and because I signed some kind of NDA somewhere.

Thing is, I setup a VM with VirtualBox in my workstation, installing a barebones Debian Sid. To have better integration with the Windows host I decided to install the VBox Linux Additions, but for some reason it was not setting up the video side of it. The error message is the one from the title:

Could not find X.org or XFree86 on the guest system. The X Window drivers will not be installed.

Thanks to this post I managed to quickly find out the reason. The step that actually tests and installs the x.org drivers is called like this:

/etc/init.d/vboxadd-x11 setup

If you run it with sh -x you will find out that it actually tests two things: the existence of /usr/lib/xorg/modules, which you can either create or just install the xserver-xorg-video-vesa package, and it tries to run X, which you will find in the xserver-xorg package.

So, TL;DR version: Just install these two packages:

sudo apt-get install xserver-xorg-video-vesa xserver-xorg

Now all works.


sysadmin

Martín Gaitán: Travis-CI para compilar y deployar tu blog estático

Travis-CI es un servicio de integración continua, gratuito para proyectos de software libre. Pero son gente tan copada que no se enojan si en vez de una suite de tests, corremos, por ejemplo, Nikola para compilar este blog y publicarlo automáticamente.

El flujo es así:

  1. Escribimos un post en el branch "fuente" (En mi caso writing) y comiteamos. Esto puede hacerse desde la propia compu, o usar el editor de Github :D
http://i.snag.gy/U4hmv.jpg
  1. Travis detecta el commit en el branch, clona el repo, instala las dependencias y ejecuta un script que corre nikola build y lo necesario para pushear el resultado (por ejemplo, la carpeta output) al branch Github pages (en general gh-pages, master en mi caso)
  2. Listo: Nikola desde la nube. For free.

Permiso, soy el CI

¿Cómo hace Travis para pushear de vuelta al repo? Bueno, hay que darle permiso. Para eso, necesitamos crear un token . Con un token, se puede pushear a un repo via HTTPS sin que pida clave usando la url https://<token>@github.com/owner/repo.git.

Pero como el archivo para configurar Travis es público (y el token es información muy sensible), lo configuramos como una variable de entorno encriptada. Para eso necesitamos el utilitario (hecho en ruby) que provee la gente de Travis:

$ sudo apt-get install ruby1.9.1-dev build-essentials
$ sudo gem install travis

$ travis encrypt GH_TOKEN=your_token

el resultado lo ponemos en el yaml:

env:
  global:
    secure: dlAoq4D...

y con eso Travis tendrá una varible de entorno global llamada GH_TOKEN que podemos usarla en nuestro script.

Podés ver el .travis.yml y el script que compila y pushea de vuelta

Martín Gaitán: Travis-CI para compilar y deployar tu blog estático

Travis-CI es un servicio de integración continua, gratuito para proyectos de software libre. Pero son gente tan copada que no se enojan si en vez de una suite de tests, corremos, por ejemplo, Nikola para compilar este blog y publicarlo automáticamente.

El flujo es así:

  1. Escribimos un post en el branch "fuente" (En mi caso writing) y comiteamos. Esto puede hacerse desde la propia compu, o usar el editor de Github :D
http://i.snag.gy/U4hmv.jpg
  1. Travis detecta el commit en el branch, clona el repo, instala las dependencias y ejecuta un script que corre nikola build y lo necesario para pushear el resultado (por ejemplo, la carpeta output) al branch Github pages (en general gh-pages, master en mi caso)
  2. Listo: Nikola desde la nube. For free.

Permiso, soy el CI

¿Cómo hace Travis para pushear de vuelta al repo? Bueno, hay que darle permiso. Para eso, necesitamos crear un token . Con un token, se puede pushear a un repo via HTTPS sin que pida clave usando la url https://<token>@github.com/owner/repo.git.

Pero como el archivo para configurar Travis es público (y el token es información muy sensible), lo configuramos como una variable de entorno encriptada. Para eso necesitamos el utilitario (hecho en ruby) que provee la gente de Travis:

$ sudo apt-get install ruby1.9.1-dev build-essentials
$ sudo gem install travis

$ travis encrypt GH_TOKEN=your_token

el resultado lo ponemos en el yaml:

env:
  global:
    secure: dlAoq4D...

y con eso Travis tendrá una varible de entorno global llamada GH_TOKEN que podemos usarla en nuestro script.

Podés ver el .travis.yml y el script que compila y pushea de vuelta

Hernán Grecco: Simulated devices in PyVISA: early preview

PyVISA started as wrapper for the NI-VISA library and therefore you need to install National Instruments VISA library in your system. This works most of the time, for most people. But sometimes you need to test PyVISA without the devices or even without VISA.

Starting form version 1.6, PyVISA allows to use different backends. These backends can be dynamically loaded. PyVISA-sim is one of such backends. It implements most of the methods for Message Based communication (Serial/USB/GPIB/Ethernet) in a simulated environment. The behavior of simulated devices can be controlled by a simple configuration in plain text. In the near future, you will be able to load this from file to change it depending on your needs.


To test it you need to install PyVISA 1.6 which is currently only available from GitHub:

$ pip install -U https://github.com/hgrecco/pyvisa/zipball/master

And then install:

$ pip install -U https://github.com/hgrecco/pyvisa-sim/zipball/master
   

For those of you interest in the internals, the plugin mechanism for PyVISA hooks at the VisaLibrary level. Mocking the Library allows for a comprehensive and powerful testing.

By the end of the week I will be blogging about another cool VISA backend which will be opened soon: PyVISA-py. It is a backend that does not require the NI-VISA library. Stay tuned!

Remember that this is an early preview. Submit your bug reports, comments and suggestions in the Issue Tracker. We will address them promptly.

Or fork the code: https://github.com/hgrecco/pyvisa-sim/

Marcelo Fernández: Comparando costos de Amazon EC2 y Google Computing Engine

Estuve mirando y por suerte son prácticamente similares las tablas disponibles en cada site (EC2 / GCE) y es relativamente sencillo compararlas [1][2].

Para sus Data Centers en USA, establecí las siguientes relaciones:

  • En las versiones de VMs “standard“, los precios son exactamente iguales, con configuraciones llamativamente similares.
  • En las versiones “high memory“, es más barato Google (la mitad), aunque Amazon te da el doble de CPUs por una VM con la misma cantidad de memoria.
    Ej: Google te da 4 CPUs / 26 GB de RAM y Amazon en cambio te da 8 CPUs para su configuración de 26 GB de RAM. Dado que estamos en “high memory“, igualé a cantidad de memoria disponible para luego decir “Google es la mitad de barato”.
  • En las versiones “large” (“high cpu” de Google), Amazon es un 15% más caro para igual cantidad de CPUs, pero te da el doble de memoria en sus VMs.

Observaciones:

  • Se desprende de lo anterior Amazon EC2 ofrece perfiles más simétricos que Google comparando la relación de cantidades de CPU/Memoria. Puede ser útil para algunas aplicaciones o no, ya que va obviamente asociado al costo.
  • Amazon tiene configuraciones con más CPUs ya que llega a 32 CPUs y más memoria también: 244 GB; Google llega a 16 CPUs y 104 GB de memoria.
  • No comparé tamaños de almacenamiento, asumo que no tiene tanta relevancia para nuestra aplicación (se disponen de varias decenas de GB en disco en ambos).
  • Amazon dice que te incluye discos de estado sólido (SSD). Google te cobra ambos (?) 0,04 USD por GB/mes el disco estándar, 0,325 USD GB/mes el SSD.
  • Fundamental para la región en la que vivo: Amazon tiene Data Center en San Pablo (Brasil), Google no; sólo sirve VMs desde USA, Europa y Asia/Pacífico.
  • Amazon tiene diferentes tipo de instancias, en este caso comparé las “Bajo demanda” aka “Dedicadas” (según el lugar que se mire en la documentación), que son las más caras. Las otras son tipo prepagas (“Instancias Reservadas”), donde según entiendo, uno abona un importe fijo y después usa X cantidad de tiempo y se descuenta del fijo.
    Hay otros tipos de instancias pero no se ajustan a nuestro uso (“Instancias Puntuales” y “Instancias optimizadas para EBS”). En este apartado, pareciera que Amazon tiene largamente muchas más ofertas y más desarrollo del negocio que Google.

Bonus Track: versus Linode.com

  • Linode tiene hasta 20 CPUs / 96 GB RAM máximo [3].
  • Linode es mucho más barato que ambos; es más simple su tabla de precios y más “1 a 1” la distribución de CPUs / RAM (4GB / 4CPUs, 8 GB / 6 CPUs, y así hacia arriba), además de que da bastante más storage en SSD.
    Por ejemplo, 4 GB / 4 CPUs en Linode: USD 0,06/hora (USD 40/mes), mientras que en Amazon estamos en USD 0,28/hora por 15GB / 4 CPUs o USD 0,105/hora por 3,75GB / 2 CPUs. Eso sí, Linode está en USA (Newark/Atlanta/Dallas/Fremont), Europa (Londres) y Asia (Tokio), no en Sudamérica.
  • Comparando Linode contra GCE:
    • 1 Linode (2 GB de RAM/ 2 CPUs / 3 TB transfer / 48 GB SSD): U$S 20/mes.
    • 1 GCE (1,70 GB RAM / CPUs “shared” (?) / 48 GB SSD): U$S 33.29/mes (no dicen si hay límite de transferencia).
  • A Linode lo conocemos los que estamos “en la pomada”, y hay casos en donde suena mucho mejor “lo tengo repartido en la nube de Amazon/Google”, nobleza obliga.

[1] http://aws.amazon.com/es/ec2/purchasing-options/dedicated-instances/
[2] https://cloud.google.com/products/compute-engine/
[3] https://www.linode.com/pricing

¿Sugerencias, comentarios?

Saludos