Every sentence to the penitentiary of a person convicted of a felony for which the maximum penalty prescribed by law is less than life imprisonment, except offenses committed by convicts in the penitentiary punishable under chapter sixty-two, article eight, section one of the code, shall be a general sentence of imprisonment in the penitentiary. In imposing this sentence, the judge may, however, designate a definite term, which designation may be considered by the board of probation and parole as the opinion of the judge under the facts and circumstances then appearing of the appropriate term recommended by him to be served by the person sentenced. Imprisonment under a general sentence shall not exceed the maximum term prescribed by law for the crime for which the prisoner was convicted, less such good time allowance as is provided by sections twenty-seven and twenty-seven-a, article five, chapter twenty-eight of this code, in the case of persons sentenced for a definite term. Every other sentence of imprisonment in the penitentiary shall be for a definite term or for life, as the court may determine. The term of imprisonment in jail, where that punishment is prescribed in the case of conviction for felony, shall be fixed by the court.