O comando tcopy

Colaboração: Rubens Queiroz de Almeida

Data de Publicação: 13 de Maio de 1997

Um comando bastante útil para manipulação de fitas ou mesmo arquivos em disco, é o comando tcopy.

Quando utilizado da forma abaixo

  % tcopy /dev/rmt0 /dev/rmt1

ele faz uma cópia de todo o conteúdo da fita contida na unidade /dev/rmt0 para a fita na unidade /dev/rmt1.

Se invocado com apenas um argumento, como abaixo

  % tcopy /dev/rmt0
  file 1: record 1: size 10240
  file 1: eof after 1 records: 10240 bytes
  file 2: record 1: size 10240
  file 2: eof after 1 records: 10240 bytes
  file 3: record 1: size 10240
  file 3: eof after 1 records: 10240 bytes
  eot
  total length: 30720 bytes

Do relatório acima, pode-se ver que a fita contém três arquivos, de tamanho 10240 bytes, contendo apenas um registro. No total a fita possui gravados exatos 30720 bytes.

É especialmente recomendado o uso deste comando após a realização de múltiplos backups em uma mesma fita, para se garantir que realmente os múltiplos backups foram gravados em locais diferentes na fita e não um em cima do outro, coisa que não acontece assim tão raramente ;-)

Ou seja, antes de fazer um upgrade baseado em backups que foram feitos em uma mesma fita, confira se tudo deu realmente certo. E nunca é demais fazer uma segunda cópia da fita.

Dica Humorística :-)

A COMPARISON OF OPERATING SYSTEMS

DOS AIR

All the passengers go out onto the runway, grab hold of the plane, push it until it gets into the air, hop on, jump off when it hits the ground again. Then they grab the plane again, push it back into the air, hop on, et cetera.

MAC AIRWAYS

The cashiers, flight attendants and pilots all look the same, feel the same and act the same. When asked questions about the flight, they reply that you don't want to know, don't need to know and would you please return to your seat and watch the movie.

WINDOWS AIRLINES

The terminal is very neat and clean, the attendants all very attractive, the pilots very capable. The fleet of Learjets the carrier operates is immense. Your jet takes off without a hitch, pushing above the clouds, and at 20,000 feet it explodes without warning.

OS/2 SKYWAYS

The terminal is almost empty, with only a few prospective passengers milling about. The announcer says that their flight has just departed, wishes them a good flight, though there are no planes on the runway. Airline personnel walk around, apologizing profusely to customers in hushed voices, pointing from time to time to the sleek, powerful jets outside the terminal on the field. They tell each passenger how good the real flight will be on these new jets and how much safer it will be than Windows Airlines, but that they will have to wait a little longer for the technicians to finish the flight systems. Maybe until mid 1995. Maybe longer.

FLY WINDOWS NT

All the passengers carry their seats out onto the tarmac, placing the chairs in the outline of a plane. They all sit down, flap their arms and make jet swooshing sounds as if they are flying.

UNIX EXPRESS

All passengers bring a piece of the airplane and a box of tools with them to the airport. They gather on the tarmac, arguing constantly about what kind of plane they want to build and how to put it together. Eventually, the passengers split into groups and build several different aircraft, but give them all the same name. Some passengers actually reach their destinations. All passengers believe they got there.

WINGS OF OS/400

The airline has bought ancient DC3s, arguably the best and safest planes that ever flew, and painted "747" on their tails to make them look as if they are fast. The flight attendants, of course, attend to your every need, though the drinks cost $15 for an orange juice. Stupid questions cost $230 per hour, unless you have Supportline, which requires a first class ticket and membership in the frequent flyer club. Then they cost $500, but your accounting department can call it overhead.

MVS AIRLINES

The passengers all gather in the hangar, watching hundreds of technicians check the flight systems on this immense, luxury aircraft. This plane has at least 10 engines and seats over 1,000 passengers. Bigger models in the fleet can have more engines than anyone can count and fly even more passengers than there are on Earth. It is claimed to cost less per passenger mile to operate these humongous planes than any other aircraft ever built, unless you personally have to pay for the ticket. All the passengers scramble aboard, as do the 200 technicians needed to keep it from crashing. The pilot takes his place up in the glass cockpit. He guns the engines, only to realize that the plane is too big to get through the hangar doors.